Do Women Perceive a Payoff from Working without Pay? A Gender Comparison of Perceived Career Outcomes of Sport Volunteering

: Gender equality among volunteers and in the labor market are essential for social sustainability. This study examines whether women value beneﬁts of sport volunteering for their job market situation signiﬁcantly differently than men. Based on signaling and social role theory, we hypothesize that women are more likely to value sport volunteering as a job market signal and as useful for career options than men. According to human capital and ecological systems theory, we hypothesize that this link depends on women’s age and national gender equality. An online survey targeting volunteers in European football clubs (in seven countries; n = 16,989) was conducted. Logistic regressions are estimated to analyze the factors affecting respondents’ agreement that sport volunteering ‘looks good on their CV’ or ‘allows to explore new career options’. The ﬁndings show that women are signiﬁcantly more likely to value sport volunteering as a job market signal but are signiﬁcantly less likely to explore new career options than men. While older women are signiﬁcantly less likely to agree, women living in more gender equal countries are more likely to agree. Our ﬁndings indicate a link between the male dominance in sport volunteering and the job market, which is determined by social sustainability.


Introduction
Social sustainability is one of three pillars besides environmental and economic sustainability that were firstly discussed in the Brundtland Commission Report [1]. Following Littig and Griessler [2], social sustainability should allow each individual to satisfy their needs in the long term. A central activity to fulfill these needs is the individual paid, but also unpaid work. Assuming that sustainability is a normative principle for the regulation of social processes and an equal distribution as well as long-term provision of resources [2], the analysis of benefits from unpaid work like volunteering that might spillover to paid work seems to be of great relevance in this debate.
Although volunteering is unpaid work in the sense that volunteers do not get a salary [3], a considerable number of men and women decide to invest time and energy to volunteer in sport in their leisure time [4,5]. It is possible that there might be benefits for the volunteers' paid jobs. Sport volunteering might be a relevant activity for the labor market since previous studies outlined that enhanced earnings are caused by sport volunteering since it serves as a signal for social skills and has a significant positive effect on perceived qualifications of applicants [6]. In these terms, Hallmann et al. [7] showed that men express higher career-related motivations to volunteer in sport than women. With respect to a significant link between sport volunteering and income, Lipford and Yandle [8] find a significant negative association, in contrast to the majority of studies finding a significant positive influence of sport volunteering on future earnings [9][10][11][12]. However, beyond studies examining income effects, the empirical findings on the link between sport volunteering and job-related outcomes are relatively scarce. By contrast, there are numerous studies which found general volunteering to improve job performance [13,14], wages [15,16], labor market participation [17,18] job satisfaction [19], and job searches [20], as well as reduce turnover [21].
While the early call of the United Nations [22] for gender equality in society and economy suggests that achieving social sustainability in this area is a key goal in general, there is also a specific demand for gender-sensible distribution of labor and equality in opportunities [2]. Along the same lines, the United Nations Entity for Gender Equality and the Empowerment of Women (UN Women), gender equality calls for "equal rights, responsibilities and opportunities of women and men and girls and boys. Equality does not mean that women and men will become the same but that women's and men's rights, responsibilities and opportunities will not depend on whether they are born male or female" [23]. Nevertheless, the goal of gender equality is still not reached as the current global gender gap report outlines that the gender gap regarding economic participation and opportunities, educational attainment, health and survival, and political empowerment is still not closed in any country [24]. However, the objective or even subjectively perceived gender equality in a country increases the likelihood of both men and women to volunteer in leisure clubs offering activities such as sports [25]. This gender gap is also evident in the leisure sector and specifically in sport: Regarding the gender distribution in sport volunteering as unpaid work, previous studies revealed a male dominance since significantly fewer women volunteer in sport than men [12,26,27], especially in grassroots football [28]. Thus, the link between (sport) volunteering and the labor market seems to be strongly related to the debate about gender equal participation and opportunities resulting from this activity and the achievement of social sustainability.
Since only 52.6 percent of women actively participate in the labor market [24], there is an on-going call for a further integration of women in the labor market [2]. Following this call, the gender differences in the valued benefits of unpaid work such as sport volunteering on the individual job market situation are highly relevant to reach this goal. The study of Wallrodt and Thieme [6] provided first empirical insights for sport volunteering, but their focus was not on studying gender differences. They presented only female applicants to potential hiring managers in their study and could only differentiate between manager's gender. Hence, their finding that sport volunteering is a signal for social skills, resulting in a positive effect on future earnings is an overall finding that was not tested for possible significant gender differences. Referring to the call of the United Nations [22,23] and the above-mentioned goal of integrating (more) women in the labor market, the question arises whether the effects of sport volunteering on the individual labor market situation are equally relevant for women compared to men.
This study analyzes the following research question: Are there possible gender differences in the valuation of the effect of volunteering in sports on their individual job market situation? The research context is European grassroots football. This context was selected as football is one of the most popular sports in Europe, but also male dominated, implying that the recruitment and retention of women volunteers is more challenging than in other sports [28,29]. Due to the public discussion of a gender earnings gap among athletes [30,31] in soccer (regarding, e.g., pay of football players [32]), the decision of women to volunteer in this male dominated sport is conscious and thus might be related to perceived job-related outcomes. In seven European countries (United Kingdom, France, Italy, Norway, Poland, Switzerland, and Germany), we conducted a survey of volunteers in grassroots football.
Moreover, and to uncover further conditions of the link between the sport volunteer's gender and the valuation of job-related benefits, we test for possible moderating effects of age and national gender equality. Hence, we want to find out whether there are significant differences in the valuation of older compared to younger women. Moreover, the research question is analyzed considering national gender equality as a potential moderator of the link between the gender of sport volunteers and the valuation of job-related benefits resulting from this activity. To exploit the relevance of national factors for our research question, the annual global gender gap rankings in 2020 were collected for each country (Table 1). This ranking shows how close countries are (in the analyzed year) to reach national gender equality regarding four dimensions: (1) economic participation and opportunity, (2) political empowerment, (3) health and survival, and (4) educational attainment. To date, no country was able to reach national gender parity so that even the top ranked countries still have a gender gap regarding these four dimensions. In the 2020 ranking, those 153 countries are considered which provided data for at least 12 necessary indicators out of 14 for the calculation of four sub-indices as well as the global index [33]. Regarding social sustainability in the sense of gender equality, Norway has the highest ranking in our sample (rank 2, score of 0.842), meaning that compared to the other 152 countries Norway had the second-highest probability to close the national gender gap regarding the four dimensions. The next-best ranking is shown for Germany (rank 10, score of 0.787), followed by France (rank 15, score of 0.781), Switzerland (rank 18, score of 0.779), and the United Kingdom (rank 21, score of 0.767). The comparably lowest rankings are evident for Poland (rank 40, score of 0.736) and Italy (rank 76, score of 0.707). Although the differences in rankings might seem to be huge at first glance, it should be considered that all analyzed European countries are listed in the first half, thus indicating the overall development towards national gender equality and social sustainability, respectively. Based on these observations, this study analyzes if the valuation of women sport volunteers is significantly differently for women living in countries with nearly reached gender equality.
Based on our empirical findings, practical implications for European football clubs are derived that can help to improve the recruitment and retention of women volunteers. Further, our findings are applicable for European football clubs considering the effect of the volunteer's age and national gender equality on gender differences of this valuation. European politics can learn from our findings whether and to what extent the promotion of sport volunteering is associated with national social sustainability in terms of gender equality and whether volunteering spills over to individuals' perceived job market situation.

Sport Volunteering as a Signal to the Labor Market
Following signaling theory [34,35], employers and employees have asymmetric information about the skills and abilities of applicants, but also current employees. To reduce the asymmetric information of employers in favor of employees to get the job or be promoted, employees or applicants might signal their unobserved skills and abilities via their application documents or curriculum vitae (CV). In this respect, individuals might use sport volunteering as a signal of altruism, intrinsic motivation, collective values, and ability to work in teams (e.g., Spera et al.; Hustinx et al. [18,36]), but also leadership and communication skills, resulting in an improved job market situation [10,37]. From this point of view, both genders might have a general interest to use sport volunteering as a positive signal in the job market.
However, women might even have a higher incentive to invest in sport volunteering due to the gender gap in the labor market. While 47% of the labor force in European countries is female, only few reach top positions in business corporations [38][39][40] or in sport clubs [41]. According to social role theory, gender is critical to the expectations attached to behavior [42,43]. When filling job or leadership positions, the attributes of applicants are compared to the attributes of current or previous officeholders [44]. Since men have dominated many jobs in history, male attributes might be predominantly associated with job or leadership qualities [44]. If women apply for job positions, role incongruities might arise since female associated attributes do not fit the (male dominated) job or leadership requirements [45]. Women might overcome such perceived incongruities by using sport volunteering as a positive signal to the job market. Moreover, they might use sport volunteering as an opportunity to elaborate new career options and, thus, improve their individual job situation. This assumption is supported by empirical evidence from Kay and Bradbury [46] finding that women reported more than men to improve their leadership skills through sport volunteering.
Based on this argument, we derive two hypotheses that on the one hand women value sport volunteering more likely as a good signal to the job market (hypothesis H1) and as an opportunity to improve the current job situation (hypothesis H2): H1a. Women are more likely than men to value sport volunteering as a good signal to the job market.
H2a. Women are more likely than men to value sport volunteering as an opportunity to improve their job situation.

The Role of Age
The decision whether or not to volunteer in sport might not only depend on individuals' gender, but also on their age. Since volunteering is a non-paid activity that most volunteers perform besides their paid job, the question arises how many years of work an individual has left before he/she retires so that labor market benefits from sport volunteering can pay off.
Following human capital theory [47], the invested time and effort in (sport) volunteering could be defined as an investment in the acquisition of particular abilities, knowledge, or skills. Previous sport research showed that sport volunteering might create and improve general human capital that is transferable from the sport sector into the job market [6]. Beyond sport, the creation or improvement of human capital by volunteering might increase the individual productivity and employee's value for employers resulting in personal benefits [48] in terms of, e.g., returns of six to seven percent of the annual earnings [10], improving public speaking skills [37], (people and) leadership skills [19,37], or communication, team, and project management skills [19], for the investing individuals in the paid job.
However, if only a few years until retirement are left, the investment in sport volunteering to improve the job market situation might be less attractive for several reasons. With increasing age, individuals have a simultaneously decreasing number of years to amortize their invested time and effort [47]. Consequently, the closer an individual gets to retirement, the lower the incentives are to volunteer [16]. This assumption is empirically evident since Kay and Bradbury [46] showed for the UK that younger sport volunteers valued this activity as a good signal listed in their CV and in applications in higher education. Further, age may determine self-selection into sport volunteering which could also significantly influence the valuation of resulting job-related benefits. Hence, the literature on age as a determinant of sport volunteering and the age structure among sport volunteers seems to be relevant in this context. For instance, Taylor et al. [12] outline that young individuals aged between 16 and 24 years have the highest probability to volunteer in sport compared to other age groups. Further, there is empirical evidence for a higher level of volunteering and moral reasoning with increasing age [49], implying that individuals value one action as being morally right compared to another as being wrong in particular situations [50]. Van Goethem et al. [49] conclude that although age is relevant for starting voluntary activities, moral reasoning is not (solely) explaining the frequency of voluntary activities since they found no significant age-related differences in (moral) involvement of volunteers. To the best of the authors' knowledge, gender differences among sport volunteers have been neglected so far. However, gender differences in the age structure might be relevant for the valuation of job related benefits of sport volunteering since men and women have a different life-cycle fertility resulting in different and/or female lower labor supply [51][52][53]. As a consequence, women have fewer years than men (if they have children) to supply labor and thus might value the job-related benefits of sport volunteering not only differently to men, but also differently depending on their current age and corresponding (plans for their future) family situation.
Young women in particular have a strong incentive to volunteer in sport and thus invest in their human capital to benefit from possible positive spillover effects on their job market situation. The majority of sport volunteers are aged between 35 and 59 years [12]. However, there is a current lack of studies linking sport volunteering with age and gender simultaneously. Scarce empirical evidence is provided for (general) volunteering with mixed findings. While Bonnesen [54] shows that there are significantly fewer gender differences in volunteering among younger individuals, she also points out the importance of higher education which significantly and positively affects volunteering of young individuals. By contrast, the study of Fyall and Gazley [43] finds no significant gender differences among volunteers for full-time working adolescents of advanced age.
Based on the above arguments as well as the presented literature, we derive another two hypotheses that women of advanced age have a lower probability to value sport volunteering as either a good signal to the job market or an opportunity to improve their job situation: H1b. Older women are significantly less likely to value sport volunteering as a good signal to the job market.
H2b. Older women are significantly less likely to value sport volunteering as an opportunity to improve their job situation.

The Role of National Gender Equality
A number of scholars have highlighted the impact of context on individual behavior, including volunteering (for a review of organizational factors see Studer and Schnurbein [55]; a process-oriented review is presented by Wilson [56]. Ecological systems theory [57] explains the importance of context to individual behavior. Various systems surround the individual, including microsystem (e.g., family, peers, clubs), mesosystem (i.e., interactions between microsystems), exosystem (e.g., local politics), and macrosystem, with the latter representing the society to which the individual belongs. Individuals living in the same country share similar attitudes, values, and ideologies of a specific national culture. Hence, living in a specific cultural background and economic environment is expected to shape individuals in a similar manner [57], supporting the role of the national context. National gender equality might be a relevant factor moderating the link between the sport volunteer's gender and the valuation of job-related benefits since the likelihood to volunteer is significantly higher for women if they live in societies with (nearly reached) gender parity and simultaneously work in female dominated organizations [58]. Likewise, national female empowerment in terms of the overall income earned as well as women representation in parliaments, management and professional positions was found to have a significant and positive influence on women volunteering [27]. Investigating voluntary leadership positions, Lesch et al. [59] found that sport organizations in German federal states with a high national gender wage gap have a significantly higher probability of a balanced distribution of men and women on their boards.
Regarding the effects of national gender equality (as an indicator of social sustainability) on women's job market situation, there is scarce literature showing that on the one hand, individuals in nations that are more "modernized" (i.e., "self-expression") [60] p. 415) tend to place less emphasis on traditional family roles and more emphasis on state economic support [61]. On the other hand, national equality and egalitarian attitudes at the individual level about men's and women's roles might be significantly correlated. This assumption is supported by previous empirical evidence for significantly raising incentives for females to support female labor force participation [62]. Further, Greenstein [63] shows that the effect of inequalities in household labor division on perceived fairness is moderated by the national context. While a significant and strong positive moderation effect is evident for married women living in countries with high social sustainability in terms of gender equality, only a minimal effect for married women living in countries with low gender equality is found.
Based on the aforementioned findings, we assume that national social sustainability in terms of national gender equality may also affect the probability that women value sport volunteering to be a benefit for their job market situation. We derive the following two hypotheses for a moderating effect of social sustainability in terms of gender equality: H1c. Women living in countries with high national gender equality are significantly more likely to value sport volunteering as a good signal to the job market.
H2c. Women living in countries with high national gender equality are significantly more likely to value sport volunteering as an opportunity to improve their job situation.

Data Collection
The data of this study were collected by surveying adult volunteers and club members in European grassroots football in the United Kingdom, France, Germany, Italy, Norway, Poland, and Switzerland. The reasoning behind this country selection was to cover a certain geographical spread across Europe in terms of Northern, Southern, Western, and Eastern Europe. One further intention was to include countries of different size, with Germany having the comparably largest national football association in terms of memberships. At the same time, we considered countries from the top as well as the lower ranking of the Gender Equality Score 2020 ( Table 1). The respective national football association assisted in developing country-specific translations of the original English questionnaire. Separate country-specific questionnaires were programmed on the platform soscisurvey. Overall, the country-specific surveys were online between November 2020 and June 2021. Based on established procedures in the literature [4,64], a top-down snowball sampling strategy was chosen to generate a convenience sample. In more detail, the distribution of the survey links was coordinated by the involved national football associations who targeted their member and volunteer directories with information in several channels, including direct e-mails, intranets, social media platforms, and websites.
Across the seven countries, n = 21,558 respondents completed the survey. The raw dataset contains n = 875 observations from the United Kingdom, n = 1075 observations from France, n = 7486 observations from Germany, n = 1134 observations from Italy, n = 2087 observations from Norway, n = 1346 observations from Poland, and n = 7756 observations from Switzerland. The cleaning of the raw dataset was conducted in several steps to ensure the reliability and validity of the data. The same person conducted the data cleaning for all seven country-specific sub-samples to ensure a consistent and comparable procedure. In a first step, responses were checked for plausibility and internal validity. For instance, observations were deleted if respondents stated an unrealistic age or volunteering hours. The responses were also checked for straight lining, namely the occurrence of the same answers to consecutive questions. The check revealed that the responses were not biased in this respect. After further excluding all non-volunteer respondents, this study was based on the volunteer subsample, containing n = 16,989 observations.

Questionnaire and Variables
The 10 min questionnaire was anonymous. Its introduction informed respondents that participation in the survey was voluntary, that they could leave the survey without any consequences, and that all data would be treated confidentially. A list of variables with corresponding summary statistics for the volunteer sample is presented in Table 2. In the survey, respondents answered questions about their agreement to statements assessing individual benefits of volunteering such as for their job market situation. Following the categorization of volunteering functions by the established study of Clary et al. [65], the dependent variables of the following estimations measure the agreement of respondents to two statements in the category of career-related benefits of voluntary work in terms of preparing new career opportunities or the maintenance of job-relevant skills. The first question asked for the respondents' agreement on a 5-point scale (from 'totally disagree' to 'totally agree') to the following statement: "Volunteering experience will look good on my CV". The dependent binary variable CV takes the value of one, if respondents valued this question with a score of 4 ('agree') or 5 ('totally agree'), and zero otherwise. Likewise, the other dependent binary variable Career options measures respondent's agreement to the statement "Volunteering allows me to explore different career options" [65]. Due to the literature-based development of these items [60], the validity of both dependent variables is ensured.
In our empirical analysis, the main explanatory variable is the respondent's gender measured by the variable Female. The reference category of this variable is being male. Further, respondents' age is included (Age) to test for a potential moderating effect on the link between gender and perceived volunteering benefits. In addition, the national score in the global gender gap index 2020 (Gender Equality Score 2020) was collected for each analyzed country from the 2020 Global Gender Gap Report [33]. This score indicates national gender gaps and is based on the population-average and measures national gender equality across the four dimensions of (1) educational attainment, (2) economic participation and opportunities, (3) health and survival, and (4) political empowerment for 153 countries. The score ranges between zero indicating the highest possible national disadvantaging of women compared to men regarding these four dimensions. By contrast, a score of '1 indicates gender equal chances regarding these four dimensions. Thus, the interpretation of this score implies that the higher the score, the closer is the country to national social sustainability in the sense of national gender equality.
Further, this study includes various factors which were found to impact labor market outcomes and were used in previous studies focusing on general volunteering [15,43]. First, we include the hours respondents invest in volunteering per month (Volunteering hours) to consider the extent of volunteering that might impact the resulting valued benefits. Therefore, a country-specific definition of sport volunteering was provided before the questions about volunteering behavior regarding, e.g., hours per month were asked. For instance, we provided this description for respondents from the United Kingdom: "Within football clubs, many people work on a voluntary basis. Volunteering is defined as any activity that willingly involves spending time, unpaid, doing something that aims to benefit the environment or someone.". For Germany, we provided this country specific description: "Within football clubs, many people work on a voluntary basis. In Germany, this means they get no payment for their work, a reimbursement of expenses, or only a small reimbursement (i.e., a maximum of EUR 2400/year for coaches/instructors and EUR 720/year for other volunteers." Moreover, we control for the weekly hours that the respondents played football (Football hours) (before the COVID-19 pandemic).
At the end of the survey, we asked for sociodemographic factors, that we include as control variables for, e.g., a possible migration background (Migrant). In more detail, we asked respondents if one of their parents have an ethnicity or nationality with a different origin than the analyzed country (e.g., a non-Norwegian nationality). This question was adjusted for each of the seven European countries. Regarding the respondents' educational level, we differentiate between a Primary degree, A-levels (i.e., a university entry degree), and a University Degree compared to the reference category of No degree including pupils. Likewise, we control for the individual monthly net income converted into purchasing power parities which consider country differences in purchasing power (Income). Dummy variables were added to the models for answer categories of socio-demographic characteristics where respondents answered with "prefer not to say" (e.g., Education n.a.).

Empirical Analysis
The empirical analysis consists of four steps. First, we value the summary statistics of the overall dataset to learn more about the surveyed respondents. Second, we conduct tests to identify significant differences between the subsamples of male and women volunteers. An independent samples Wilcoxon ranksum-test is employed for continuous variables, while a Chi 2 -Test is conducted for nominal variables.
In a third step, the six hypotheses are tested by estimating logistic regression models since both outcome variables CV and Career options are binary (dummy) variables [66,67]. The use of logistic regressions is appropriate since it allows estimation of the marginal effects of the women's probability to value sport volunteering to be beneficial for their CV or career options. We estimate a model including the explanatory variables Female, Age, and Gender Equality Score 2020 to test hypotheses H1a and H2a and the unconditional effect of gender. In a fourth step, we estimate a second model for the interaction between (female) gender and age (hypotheses H1b and H2b) by adding the interaction term Female*Age. Within the same model specification, we further test for a conditional effect of women living in countries with a high Gender Equality Score 2020. The interaction term Female*Gender Equality Score 2020 is implemented to test hypotheses H1c and H2c. Recall that we analyze a cross-sectional dataset, meaning we have to exclude country dummies since they would be perfectly correlated with the particular Gender Equality Score 2020 variable.
The predictive capacity of each model is presented in terms of the Pseudo-R 2 , the adjusted Mc Fadden R 2 , as well as the Akaike information criterion (AIC) for each estimated model. We further cluster standard errors and provide the results of Wald Chi 2 tests and the log-pseudo likelihood, to value the quality of our logistic regression models.
In order to check for multicollinearity in our regression analyses that might distort our coefficient estimates, we examine bivariate Spearman correlations among all variables.
The corresponding results are presented in Table 3. As all bivariate correlations are at a comparably low level and far away from the critical value of 0.8, there is no indication that the following analyses might be distorted due to multicollinearity [68].   Table 2 includes the summary statistics for the full sample, while Table 4 presents the means for the male and female subsamples as well as the corresponding significance tests. In our full sample, we find on average an agreement to the statement that sport volunteering 'looks good on the CV' with 59.7% ( Table 2). The calculation of the corresponding dummy variable reveals that a significant higher relative share of women volunteers (69.2%) agreed to this statement, compared to the share of men volunteers (58.3%) ( Table 4). This observation is in contrast with the low differences in the relative shares of women volunteers (37.3%) who agreed to the statement that sport volunteering 'allows to explore new career options' compared to the share of men volunteers (36.4%) ( Table 4). Likewise, we observe for the full sample that only 36.5% of respondents agreed to this statement ( Table 2).

Summary Statistics
Regarding the main explanatory variable, the summary statistics show that 12.6% of the analyzed volunteers are female ( Table 2). The mean age of respondents is 44 years (Table 2), with men being significantly older (on average 44 years) compared to a mean age of 40 years for female respondents (Table 4). In the female subsample, the average Gender Equality Score 2020 is significantly higher (0.782) than for male respondents (0.793) ( Table 4). In our sample, men volunteers spent significantly more hours on this activity (on average) with 35 h compared to 29 h per month of women volunteers (Table 4). While the overall mean of football hours is 3.8 h per week (Table 2), men play significantly more football per week with a mean of 4 h compared to on average 2 h for women (Table 4). In the full sample, 9.3% of volunteers have a migration background (Table 2), with a significantly higher share among male respondents (9.6%) compared to female respondents (7.6%) ( Table 4). On average, 7.7% of the analyzed volunteers have a physical or mental disability ( Table 2). The relative share of women volunteers with a disability (10.2%) is significantly higher than the relative share of men volunteers with a disability (7.3%) ( Table 4). The full sample consists of on average one percent of respondents without a degree ( Table 2). Significant gender differences are not evident here (Table 4). By contrast, 36.7% of respondents have a primary degree (Table 2), with the share being significantly lower among female sport volunteers (30.2%) than among their male counterparts (37.6%) ( Table 4). In turn, we find a significantly higher share of female respondents having an A-level degree (26.3%) compared to the share of male respondents (23.9%) ( Table 4) which is quite similar to the share of 24.1% in the full sample (Table 2). With respect to a university degree, the overall share as well as those among male respondents is about 35 to 36% (Tables 2 and 4). Conversely, the share of female respondents is 5 percentage points higher and thus significantly different compared to the share of the male subsample (Table 4). On average, the personal monthly net income of men respondents is significantly higher (2.58 this is equal to 3784 Euros) than that of female respondents (2.00 which is equal to 2941 Euros) ( Table 4). Table 5 summarizes the results of the logistic regressions analyzing all six hypotheses. Models 1 and 2 present the corresponding findings of the estimations testing the agreement to the statement that sport volunteering 'looks good on my CV' (with CV as the dependent variable). The findings reveal that women volunteers have a significantly higher likelihood to agree to the statement that sport volunteering 'looks good on my CV' by 6.5 percentage points (model 1, Table 5) than men volunteers. Thus, hypothesis H1a is supported by this model specification. With respect to a possible age effect among women volunteers (H1b), the interaction term Female*Age shows that being an older woman is significantly negatively associated with the likelihood to agree to this statement by 0.5 percentage points (model 2, Table 5). Thus, hypothesis H1b is supported as well. Moreover, women sport volunteers living in countries with a high Gender Equality Score 2020 (Female*Gender Equality Score 2020) have a significantly higher probability to agree this statement. Consequently, hypothesis H1c is supported, too.

Regression Analysis
With respect to hypotheses H2a, H2b, and H2c, models 3 and 4 (Table 5) estimate the probability that the analyzed sport volunteer agrees to the statement that sport volunteering allows to 'explore different career options' (Career options). The logistic regressions show that women volunteers have a significantly lower probability by 2.5 percentage points to agree to this statement than men volunteers (model 1, Table 5). Hence, we find no confirmation for hypothesis H2a. Further, the analysis of possible age effects among women volunteers shows that older women have a significantly lower probability by 0.7 percentage points to agree than men volunteers (model 2, Table 5). Consequently, hypothesis H2b is supported. Moreover, we find that women sport volunteers living in a country with a high level of (nearly) national gender equality (Female*Gender Equality Score 2020) have a significantly higher probability to agree to this statement by 75.1 percentage points. Hence, hypothesis H2c is also confirmed. Table 5. Logistic regressions (n = 16,989) to explain the probability for an agreement to 'volunteering looks good on my CV' (CV) (H1a-H1c, Models 1-2) and 'volunteering allows to explore new career options' (Career options) (H2a-H2c, Models 3-4).

Discussion
The goal of this study was to analyze whether women value the effect of volunteering in grassroots football on their individual job market situation significantly differently than men. Based on a survey conducted among volunteers in football clubs in seven European countries, a descriptive analysis as well as logistic regressions were chosen to answer the research question. Similar to the findings of previous literature, that there is a male dominance among sport volunteers [12,26,27], especially in grassroots football [28], only 12.6 percent of the responding European football club volunteers in our survey data were female.
Regarding the valuation of job-related benefits from sport volunteering, 59.7% of respondents agreed that volunteering experience will look good on their CV. This finding is in line with Wallrodt and Thieme [6] who present evidence that sport volunteering might be a signal for social skills to potential employers. For this statement, we find a significantly higher agreement for women volunteers than for men volunteers, thus indicating a first descriptive gender difference in the valuation of potential labor market outcomes of sport volunteering. Regarding volunteering as an opportunity to explore different career options, slightly more than one third of the respondents (36.5%) agreed with this statement. By contrast to the previous statement, we find no significant difference for the male and female subsamples. Comparing these descriptive findings already indicates that sport volunteers rather value this activity to be valuable as a signal to the job market, but not necessarily as a chance to exploit new career options.
The estimations of logistic regressions significantly confirm hypothesis H1a, which is based on signaling and social role theory, meaning that women volunteers have a significantly higher probability than men volunteers to agree that sport volunteering is a good signal to the job market. Contradictory to our theoretical argument (hypothesis H2a), women have a significantly lower likelihood to agree that sport volunteering is an opportunity to improve their job situation. One explanation for this finding could be the empirically evident male dominance among sport volunteers in grassroots football [28] that we also observe in our data. In contrast to Hallmann et al. [7] finding women to have higher career-related motivations to volunteer in leisure clubs (like sports), our study shows that those women who made experiences as sport volunteers perceive significantly lower job-related benefits than men volunteers. Due to the male dominance in the sport voluntary sector and the resulting so called 'old boys network', women might be disadvantaged and are not sufficiently considered in the network of men volunteers so that they do not value sport volunteering as a chance to push their career compared to men.
After exploiting the unconditional effect of the sport volunteer's gender on the valuation of job-related benefits, this study considered two further conditions that might impact possible gender differences of such valuations. The first tested moderator was the respondent's age. While Taylor et al. [12] found that sport volunteers are more likely to be young (with 16 to 24 years), the mean age in our sample rather tends to be mid-aged with 44 years. We find that women volunteers in our sample are on average significantly (4 years) younger than men. Based on human capital theory, we hypothesized that older women have a significantly lower likelihood than younger women to agree that sport volunteering is either a good signal to the job market or might be an opportunity to improve the job market situation. In line with Kay and Bradbury [46], our estimations show in each model specification that older sport volunteers have a significantly lower probability to agree that sport volunteering is a good job market signal. Our findings further reveal that the same is evident for the agreement that sport volunteering provides the opportunity to improve the job market situation. Looking at gender differences by also considering the respondent's age, we find confirmation for our theoretical hypotheses (H1b and H2b) that older women volunteers have a significantly lower likelihood to agree that sport volunteering might either be a good job market signal or an opportunity to improve their job market situation than younger women volunteers. These findings do not only support our argument based on human capital theory, but also imply a possible explanation corresponding to the research on life-cycle fertility and female labor supply. According to this literature, women have less time to supply labor if they have children [51][52][53] than men. Taken together with Becker's [47] human capital argument, it becomes clear that older women volunteers have a significantly lower likelihood to value job-related benefits from sport volunteering than younger women or even older men volunteers. This might be because they not only have less time to amortize the invested time and effort in the voluntary activity in their paid job than younger women, but also have less time for the amortization compared to older men (if they have children).
As a second condition and based on ecological systems theory, we further predicted that women living in countries with high national gender equality have a significantly higher probability to agree that sport volunteering might be a good signal to the job market (hypothesis H3a) or an opportunity to improve the job market situation (hypothesis H3b) than men volunteers. Even though we find different impact directions for the unconditional effect of being a woman volunteer on the likelihood to agree that sport volunteering might be a good job market signal (positive link) or provide the opportunity to improve their own job market situation (significant negative link), the conditional effect of women sport volunteers living in countries with high national gender equality is significantly positive for both tested job-related benefits. Thus, our findings indicate that women who are faced with nearly reached gender equal opportunities, e.g., in the job market have a significantly higher probability to value sport volunteering to be beneficial for their job market situation. Hence, it can be argued that women living in countries with nearly reached gender equality are better integrated in the job market [2], thus have (more) opportunities to earn a living, work full-time, and pursue a career [69], but are also better integrated in the voluntary sector [43]. Then, these women also might have a higher valuation of sport volunteering as a job market signal that they can really make use of compared to women living in countries with gender imparity hindering them to equally participate in the job market. In countries with nearly gender equal opportunities to pursue a career, women might benefit significantly more from improved leadership skills [46] through sport volunteering than women in countries with low gender equality. Especially regarding the significantly lower likelihood of women to value sport volunteering as a chance to improve their job situation, one might argue that women living in countries with gender imparity have only few career opportunities in the job market so that they focus less on their career. Consequently, these women might thus not (even) consider a possible positive spillover effect of sport volunteering on their job market situation. This argument is in line with Lesch et al. [59] arguing that women with low or even no gender equal treatment especially in the national job market invest their time and skills rather in leisure activities, like sport volunteering [17], but not in professional work. Building on this argument, our findings of a negative unconditional effect for (all) women and a positive conditional effect of women living in countries with nearly reached national gender equality imply that women living in countries with a low level of gender equality are less expected to consider sport volunteering as an opportunity to overcome the national gender imparity in the job market.
Summarizing, the findings of this study reveal that the national social sustainability in the sense of nearly reached national gender equality has a positive impact on the link between the leisure activity of sport volunteering and the valuation of positive spillover effects on the individual job market situation of women. However, our findings regarding the women's age also outline that the remaining time to amortize the invested time and effort in sport volunteering via benefits in professional work (by also considering further shortening of the years of labor supply due to having children) is a critical factor that should be considered by sport organizations experiencing problems regarding the recruitment and retention of volunteers, especially women volunteers. However, the marginal effects of our estimations outline that the positive effect of women sport volunteers living in countries with a socially sustainable environment is larger than the negative effect for older women.

Conclusions
The aim of this study was to analyze possible gender differences in the valuation of jobrelated benefits of sport volunteering. Drawing on a detailed theoretical framework based on signaling theory, social role theory, human capital theory, and ecological systems theory, we extend the previous literature and provide arguments as to why women are more likely to appreciate job-related benefits from sport volunteering compared to men. We extend our basic theoretical assumptions by presenting further arguments on two moderating factors of the link between volunteer gender and the perception of labor market benefits. Our findings imply that both the personal situation of women sport volunteers, illustrated by their age, as well as the social sustainability of the environment they live in, in terms of national gender equality, may either lower (age) or even increase (national gender equality) the likelihood of perceiving job-related benefits of sport volunteering. The findings of our analysis revealed that political incentives that encourage women to volunteer in sport might help to overcome the hurdles of the 'old boys network' so that women volunteers might use sport volunteering to push their career, and in turn, overall more social sustainability in terms of gender equality in the job market might be achieved in the future.
These findings yield several implications for European grassroots football clubs. On the one hand, football clubs might recruit more women volunteers by actively communicating job market benefits of sport volunteering to interested women. As our empirical analysis showed, women in particular might value the benefit from signaling sport volun-teering in their resume. On the other hand, our findings also indicate that the compatibility of voluntary work and career is an important signal for interested women to convince them to volunteer in sport. The positive and comparably large effect for women living in countries that have nearly reached national gender equality affecting the probability of perceived job-related benefits of sport volunteering emphasizes the importance of national politics to further push the aim of national gender equality (in Europe).
While our study analyzes the perceived job-related benefits of those women who decided to volunteer in sport, there might be hidden potentials that women volunteers need to explore to unfold (at least) the same benefits as men volunteers. Women might excel themselves and their sport volunteering activity to current and potential employers, by actively communicating the acquired skills and qualifications that are helpful to pursue their job-related tasks and the employer's goals. The greater challenge for women sport volunteers might be to explore career options in male dominated sports such as football. Thus, emphasizing the international aim towards gender equality in the labor market but also in football [30,31] might motivate women sport volunteers to actively reach out to the 'old boys network' of sport volunteers and to firstly discuss potential structural disadvantages of women volunteers leading to less perceived job-related benefits compared to men volunteers. Secondly, reaching out to men sport volunteers and discussing how they generate and benefit from sport volunteering in terms of career options might incentivize women sport volunteers on how to actively connect with employers and important bridging individuals between the voluntary sport sector and the labor market.
Admittedly, this research is not without limitations, which imply avenues for future research. While this study is based on a survey targeting football volunteers in European countries, the presented findings might be different in other sports and countries. Moreover, the situation assessed in the survey is related to the period before the COVID-19 pandemic, so that future research might replicate this study to find out if the presented associations also hold after the pandemic. Another limitation of our study is that the distribution of observations among countries is comparably unbalanced so that we were not able to find robust empirical findings per country. However, we control for the country that a respondent lives in so that the analysis captures possible distortions. Since this study uses cross-sectional data, we can only present correlative rather than causal findings. Future studies might use longitudinal data to investigate causal effects (while eventually compromising survey anonymity), but also the effects of the COVID-19 pandemic on the expected labor market benefits of sport volunteering for men and women. While our study uses rather general information on the current job, future studies might also investigate in more depth the extent to which the human capital gathered through sport volunteering is beneficial for particular hierarchical levels and job sectors. Therefore, the consideration of family and educational backgrounds might be of central interest.
Author Contributions: Conceptualization, K.S. and P.W., methodology K.S. and P.W., formal analysis, K.S.; investigation, K.S.; writing-original draft preparation, K.S., writing-review and editing, P.W., T.F.T. and L.E.D. All authors have read and agreed to the published version of the manuscript.
Funding: P.W. and L.E.D. received funding from the UEFA for the data collection and research, but not for this publication. We acknowledge support for the publication costs by the Open Access Publication Fund of Bielefeld University and the Deutsche Forschungsgemeinschaft (DFG).
Institutional Review Board Statement: Not applicable. Approval by an Institutional Review Board was not necessary.

Informed Consent Statement: Not applicable.
Data Availability Statement: The data presented in this study are available on request from the corresponding author.

Conflicts of Interest:
The authors declare no conflict of interest.