Achieving Cultural Sustainability in Museums: A Step Toward Sustainable Development

Cultural sustainability is increasingly being perceived as a fourth dimension of sustainable development. So far, some studies have debated the way in which cultural sustainability can lead to economic, social, and environmental benefits, while others have highlighted how the classic pillars of sustainability can help museums to achieve their core cultural mission. However, empirical studies regarding cultural sustainability in museums are scarce. Thus, one of the aims of our research was to fill this gap by developing several econometric models that explain the influence of heritage exposure; environmental behavior; openness to the public; and effectiveness and performance in collecting, preserving, and researching the cultural heritage. A second aim was to advance the current knowledge in this field by creating an integrated frame that explains the interconnections between different variables that help museums become sustainable, as well as the place and role of cultural sustainability within the overall framework of sustainable development. To achieve these goals, an in-depth analysis of the literature was followed by a survey of 86 Romanian museums. The results show that the ability of museums to reach cultural sustainability is influenced by components of their social and economic performance, while environmental behavior proved to be insignificant.


Introduction
Sustainable development is increasingly seen as being composed of four dimensions; namely, economy, society, environment, and culture [1]. There are multiple reasons for adding culture to the traditional three-pillar construct of sustainability. Culture includes the beliefs, values, practices, and aspirations of a society; the way in which values are expressed and applied concretely in the day-to-day life of that society; and the processes and mediums through which the preservation and further transmission of values take place [2].
In order to reach environmental responsibility, social justice, and economic development, a certain set of values and behaviors should be developed among individuals [3]. As a sustainable society depends on a sustainable culture, any action to achieve sustainable development goals must take into account not only the natural, social, and economic environment, but also the cultural environment. If the culture of a society disintegrates, so will all its other components [2]. Thus, 'culture is essential for a sustainable society to be possible' [4].
On the basis of these considerations, in 2001, UNESCO's Universal Declaration on Cultural Diversity launched a process that aimed to add culture as the fourth dimension of sustainability [5]. Measures adopted to increase effectiveness and performance are an important part of economic sustainability [14] that allow a museum to fulfill a larger number of cultural objectives with the same amount of resources. Despite the variety of economic, social, cultural, and environmental benefits generated by museums, one of the great problems for these institutions is under-funding [17]. Consequently, during the last economic crisis, many museums were compelled to apply strategies to improve their competitive advantage and effectiveness [43]. Those who failed to implement such strategies were forced to sell works from their collections, or even merge with other museums to survive [17]. Given the limited and often insufficient financial resources of museums and the fact that they must incur certain costs in order to perform conservation and restoration activities [45], we assume that an increase in effectiveness and performance can positively influence cultural sustainability.

Hypothesis 1 (H1). Cultural sustainability is positively related to effectiveness and performance.
Cultural sustainability involves the protection of museum heritage. To preserve the artefacts, museums must install safety and security systems and ensure adequate microclimate conditions in exhibitions and warehouses [14]. Light, humidity, and temperature are the most important parameters, which require special attention. By using modern devices, museums should not have difficulties in keeping these parameters between the recommended limits. However, other factors caused by climate changes and natural imbalances are more difficult to control and may seriously damage museums' collections. Drought, floods, fires, hurricanes, and landslides are just some of these factors [46]. Therefore, to protect the integrity of their cultural assets, one of the first duties of museums is to keep the natural environment safe [47] (pp. 7,8). Green practices help to control the microclimate conditions inside and outside the museum, which contributes to the achievement of heritage preservation objectives [47] (p. 2). Hence, we argue that there is a positive connection between the environmental behavior of museums and their cultural sustainability.

Hypothesis 2 (H2).
Cultural sustainability is positively related to environmental behavior.
The social contribution of museums to sustainable development consists of building new relationships with their communities and particular groups of people [48], so as to stimulate intercultural understanding and acceptance [49], social cohesion, and a sense of belonging [50,51]. In this context, inclusiveness and openness are basic requirements for a socially responsible museum [48]. Beside improving the quality of people's lives, a socially responsible museum, with a visitor-centric perspective, is more attractive to community members and tourists [25]. This can lead to an increase in the financial resources the museum manages to attract from various sources (visitors, government, donors, sponsors). As a result of this financial support, the museum can successfully fulfill its primary mission of enriching, preserving, and researching cultural heritage. Therefore, we can state that a positive connection exists between cultural sustainability and the museum's openness to the public.

Hypothesis 3 (H3).
Cultural sustainability is positively related to openness to the public.
Social interaction and interconnection between people from all social classes and ethnic communities [51] (p. 359) take place within exhibitions or at other events and activities organized by museums around their collections [52,53]. Therefore, heritage exposure is the primary way in which museums use the cultural resources they hold to serve the society and generate cultural vitality. At the same time, exhibitions are the basic product that differentiates museums from other cultural institutions and the reason most visitors choose to enter a museum. Related services such as restaurants or educational programs can improve the quality of visiting experience, but in the absence of exhibitions, they would not have the capacity to produce the same socio-cultural impact in the community. Also, exhibitions can increase the attractiveness of a museum, and in this way, the revenue attracted by it. In turn, high incomes allow a museum to achieve its heritage conservation goals to a greater extent. Because exhibitions are an important way to generate a high social impact, but also to financially sustain a museum, worldwide museum strategies focus on increasing the exposure of collections over the limits imposed by a museum's space. The practical application of this strategy involves organizing temporary exhibitions in other locations or even opening exhibition centers or satellite museums abroad [54][55][56]. On the basis of these considerations, we argue that there can be a positive link between cultural sustainability and heritage exposure.

Hypothesis 4 (H4).
Cultural sustainability is positively related to heritage exposure.

Survey Structure
To test the hypotheses regarding the factors that might have an influence on cultural sustainability in museums, we opted for a quantitative analysis based on the application of a questionnaire at national level. The reasons that prompted us to opt for this research tool are that it requires less time and financial resources than other tools and allows more data to be collected from an extended geographical area. At the same time, the possible weaknesses of a questionnaire-based research, such as the fact that the qualitative level of the data collected depends on the honesty of the respondents and the degree to which they understand the questions, are similar to those of other research instruments [57].
The first step in designing the survey was to search and identify in the literature other relevant questionnaires regarding the sustainable development of museums. Thus, we noticed that previous research focused on assessing museum effectiveness and performance [58], improving energy efficiency [59], identifying sustainability initiatives and measures adopted by museums [60], and evaluating the satisfaction of museum visitors [61]. Although those studies include some economic, environmental, and social sustainability issues, none of them cover all four dimensions of sustainability, and the cultural pillar is almost absent within them. Therefore, starting from the theoretical findings and the previous empirical research conducted in the field of museum sustainability, we designed a new questionnaire able to collect relevant data for testing our hypotheses. Before distributing the questionnaire at national level, it was first refined and improved based on the opinions expressed by three faculty members, a statistician, and several museum employees. The clarity of the items and the ability of museums to answer them was checked by applying the survey within the County Museum of Art 'Baia Mare Artistic Centre'.
The final version of the questionnaire consists of two parts. The first part includes 27 items that use a five-point Likert scale (1-total disagreement, 5-total agreement). Six items are related to cultural sustainability and investigate the ability of museums to collect, preserve, and research cultural heritage. Effectiveness and performance are measured through seven items that assess different output-input ratios (the results of the museum compared with the resources used to achieve the results). The five items dedicated to environmental behavior focus on the measures taken by museums to improve the use of electrical and thermal energy, fuel, water, and materials. Social relevance was split into two variables: heritage exposure (two items) and openness to the public (seven items). Heritage exposure measures the efforts made by a museum to make its heritage available to the public by organizing exhibitions inside and outside of the museum walls. Openness to the public evaluates the ability of a museum to offer attractive products and services on the market, satisfy the cultural needs and desires of its users, collaborate with community members for organizing various exhibitions and events, and attract a wide and diversified audience that is representative of all community groups and ethnic minorities [14]. The second part of the survey includes 16 questions related to the characteristics of the respondents and of the museum to which they belong. The questionnaire used for this research can be consulted in Appendix A.
In addition, the contact details of the respondent are requested at the end of the questionnaire (name, address, email). Despite the potential risk that the response rate would be affected by requesting this information, the reasons we decided to keep the contact data in the questionnaire are to avoiding duplication of answers from the same institution, the possibility of having a clear list of responding and non-responding museums, the possibility of re-contacting institutions that have not responded before a certain time, and the possibility of asking for clarifications in the case of incomplete questionnaires. Respondents were assured that their responses would be kept confidential and without their prior agreement, no material would be published suggesting a possible link between their museum and their answers.

Museum Sector in Romania
After setting up the research hypotheses and developing the questionnaire, our next step was to analyze the size, structure, and main characteristics of museums in Romania in order to identify the conditions that must be fulfilled by the sample.
According to the National Institute of Statistics (NIS) [62], the Romanian network of museums and public collections included 431 units in 2015 (without branches and satellite museums). Given the characteristics of our research, from this total, we excluded monuments, botanical gardens, zoos, aquariums, dendrological parks, and natural reservations (41 units). However, no data were available regarding the number of museums and the number of public collections. Thus, despite the mission, aims, and activities of museums being more complex than those of collections, in the lack of separate evidence regarding the two categories, we had no choice but to continue our analysis based on the premise that in Romania, there are 390 museums and public collections. The structure of these museums and collections depending on their type, the heritage objects they own, and the number of visitors recorded by them in 2015 is presented in Table 1. Considering the relevance of the heritage, the Romanian network of museums and public collections is structured as follows: 70% local museums and collections, 13% county museums and collections, 5% regional museums and collections, and 12% national museums and collections. Regarding the ownership, 18.79% of museums and collections are private, while 81.21% are public [63].

Survey Methodology
As the NIS does not provide the names and contact details of the museums included in their statistical reports, in order to further perform our research, we tried to identify the total population of Romanian museums. At this stage, the database 'Museums and Collections in Romania', made available online by the National Heritage Institute (http://ghidulmuzeelor.cimec.ro), proved to be particularly useful. This database allows museums and collections to be sorted by county, locality, and type, and also provides their contact information. Unfortunately, we found that many museums do not have an email address or website, which made it impossible to send the questionnaire online to these museums. By accessing each unit in this database, we were able to create a list with 186 museums that have an email address and a distinct manager/administrator. Museums with the same manager were counted only once because they were part of the same organizational structure, and the survey questions were designed for an organization as a whole.
On 3 October 2016, the questionnaire was sent by email to the museums included in the list. Given that the research was conducted at national level, we opted to manage the online questionnaire distribution using the facilities offered within the Google Drive platform. At the same time, printed questionnaires were collected from the museum managers who attended the National Conference of Cultural Managers (Bucharest) and the General Meeting of the National Network of Romanian Museums (Sibiu) from 29 October to 2 November 2016. The data collection ended on 29 November 2016, with 87 responses and a response rate of 46.77%. The Google Form survey was set up to accept the submission only if all the required questions were answered. In this way, very few cases of partial response were recorded. However, one of the printed questionnaires had to be removed as a result of incomplete answers. Therefore, the statistical analysis is based on 86 valid responses.

Sample Profile
Museums from all eight development regions of Romania completed the survey. The smallest number of answers (five) come from the Southwest Region and the highest number of completed questionnaires were collected from the Northwest Region (17). The last column of Table 2 shows the representativeness of each region, calculated as a ratio between the number of responses received and the number of museums and public collections in the region. Thus, if we take as a reference the total number of museums and public collections, it can be seen that each region's sample representativeness is over 11%. Because of the large number of museums in the Center Region (123), it has the lowest representativeness (11.38%), even though it recorded more responses than other regions (14). At the opposite end is the Southeast Region, with the fewest museums (19) and the highest sample representation (52.63%). Overall, the ratio between the collected responses and the total number of museums and public collections that exist at national level is 22.05%. Therefore, given that the answers come from all regions of the country, and the fact that a significant part of the 390 units is public collections and not museums, we believe that the research results can be considered representative at national level. Table 3 shows the structure of the responses according to museum type. Of the total number of replies, most come from general and mixed museums, followed by art museums and history and archeology museums.  Table 3 shows that almost all museums of natural history and science completed the questionnaire (90%). They are followed by general museums and technology museums with a representative rate of 55.56% and 35.71%, respectively. Ethnography museums and art museums have the smallest degree of representation. This is explained by the fact that the vast majority of public collections that could not be excluded from the total population belong to these two categories. Also, specialized museums are slightly under-represented (13.79%), because many of them are managed by private enterprises and could not be contacted or did not want to respond.
Regarding the relevance of collections, the sample has the following distribution: county museums-30 answers; local museums-21 answers; national museums-23 answers; and regional museums-12 answers. If we analyze this structure in relation to the number of existing units at national level, we can notice a good degree of representation of national museums (46%), regional museums (57.14%), and county museums (52.63%). Because most public collections are of local relevance and could not be excluded from the analysis, the representativeness of local museums could not be accurately established. In the literature, it has frequently been stressed that museums with a heritage of high cultural and artistic relevance are more likely to have a higher degree of public success [39,64]. Thus, we used the museum's relevance as a control variable in order to increase the accuracy of our results.
Regarding the number of visitors in 2015, 27.9% of the interviewed museums reported fewer than 5000 visitors, 37.2% registered between 5000 and 30,000 visitors, and 34.9% exceeded 30,000 visitors. As the number of visitors is an important criterion according to which the attractiveness of a museum is appreciated [17,65], in order to not influence the research results, we used the number of visitors as a control variable.
At the same time, it was found that museums belonging to the National Network of Romanian Museums (NNRM) were more open to completing the questionnaire. Of the 186 museums included in the list, only 64 were members of the NNRM. However, 53 of the 86 responses came from museums belonging to the NNRM. For this reason, we believe that NNRM membership is a possible influencing factor on museum sustainability, which is why we use it as a control variable.
Because of the variety of the collected data, we concluded that the sample can be considered representative of Romanian museums. Therefore, we continued our statistical analysis in order to test the hypotheses. The most important findings are presented in the next section.

Results
The relationship between cultural sustainability (CS) and the independent variables discussed above was empirically examined using the following hypothetical research model: CS (cultural sustainability) is the dependent variable (DV) and denotes the ability of museums to collect, preserve, and research the heritage; EP, EB, OP, and HE are the four independent variables (IVs) that indicate a measure of effectiveness and performance (EP), environmental behavior (EB), openness to the public (OP), and heritage exposure (HE); R (relevance), V (the number of visitors), and NW (member of the NNRM) are the three control variables; β0 to β7 are the model coefficients; and ε is the error term added to show the inaccuracy of the model.
The statistical processing of the collected data and the analysis of the relationship between the DV and the IVs were performed using IBM SPSS 22.0 software.
Initially, the dependent variable was analyzed in order to evaluate the distribution of the collected data. The descriptive statistics for the items included in the cultural sustainability scale show that mean and median are almost equal, while the highest standard deviation is 1.246 (Table 4). The negative values of the skewness coefficient indicate in all cases a deviation to the right from the empirical distribution. This means that a greater number of museums declared that their heritage is very well preserved, compared with the number of museums that did not agree with this statement. The kurtosis is used to measure the 'flatness' or the 'peakedness' of a distribution, and a value close to zero denotes a normal distribution. In our case, three items recorded positive values of kurtosis, which indicates that the distribution of the answers in these cases is more peaked than normal, while the other three items recorded negative kurtosis coefficients, which is a sign of 'flatness'. The lowest kurtosis value can be noticed in the case of the fifth item, which denotes that Romanian museums tend to have difficulties regarding the inclusion of their heritage in a digital database. This result is in line with a previous research conducted by Fanea-Ivanovici [10], who revealed that Romania has only 154,830 items included in Europeana, which places it in 24th position out of a total number of 44 providing countries. However, besides the first item, the skewness and kurtosis coefficients have values between ±2, which are considered acceptable [66]. The next step was to verify the reliability and internal consistency of each scale included in the questionnaire using the Cronbach's alpha coefficient [67].  Table 5). The items included in the five scales are also intercorrelated (Cronbach's alpha coefficient for the total scale is 0.922), which means they can be used to measure the sustainability of museums. The adequacy of the sample for each variable included in the model was measured using the Kaiser-Meyer-Olkin (KMO) test. The results of the KMO test exceed the minimum level of 0.5 [68] ( Table 5) and the Bartlett's Test of Sphericity proved to be significant as well (p < 0.001), which means the collected data are suitable for structure detection (factor analysis).
Therefore, we used confirmatory factor analysis (CFA) to evaluate the extent to which the items explain the latent variables [69]. The last column of Table 5 shows that for the variable 'cultural sustainability', the six items explain the variance by 57.795%. For the variable 'effectiveness and performance', the seven items explain the variance by 51.470%. For the variable 'environmental behavior', the five items explain the variance by 76.327%. For the variable 'openness to the public', the seven items explain the variance by 45.004%. In the case of 'heritage exposure', the two items explain the variance of the latent variable by 76.177%.
The results of the CFA indicated that latent variables can be expressed as a linear combination of items. Thus, based on the items included in each scale, we generated five synthetic variables. Subsequently, to verify the links that exist between latent variables, the correlation coefficient was calculated. This coefficient may have values between −1 and +1. Values close to +1 indicate that there are direct positive relationships between two variables, while values close to −1 indicate the existence of negative associations [70] (p. 24).
The coefficients presented in Table 6 show the existence of positive, significant correlations between cultural sustainability and all four exogenous variables. Because the coefficient does not tell us the extent to which one variable depends on another, the results can be interpreted in a double sense. On the one hand, a museum that has taken all necessary steps to preserve, conserve, and research its collections has greater potential to organize attractive exhibitions for the public and to carry out social and environmental actions and activities. In turn, the social performance of the museum can lead to an increase in the number of visitors and financial resources it attracts, while environmentally responsible behavior can reduce the consumption of natural and material resources. Thus, effectiveness and performance indicators are positively influenced by increasing output and decreasing input. On the other hand, organizing attractive exhibitions and meeting the community's needs are factors that have the capacity to help a museum attract the financial resources needed to fulfill its goals of preserving, conserving, and researching the cultural heritage. Furthermore, increasing effectiveness and manifesting environmentally responsible behavior by reducing the consumption of natural resources (energy, water, materials, etc.), reusing resources as much as possible, and recycling what can no longer be used in the current form [47] (p. 6) allow a museum to achieve more cultural objectives with the same amount of financial, human, and material resources.
In order to find out if there is any difference between the cultural sustainability of museums with various characteristics, we have used the analysis of variance (ANOVA). The ANOVA test infers whether there are any significant differences in the means of the corresponding population groups [71]. The null hypothesis assumes that all the museum groups have an equal cultural sustainability mean. Thus, by performing this test we intended to answer the following questions: (1) Does the number of visitors have any effect on cultural sustainability? Do museums from the three categories differ significantly in achieving cultural sustainability? Which group has a higher cultural sustainability? (2) Does the relevance of museums, according to their cultural heritage, have any effect on cultural sustainability? (3) Does membership of the NNRM have any effect on cultural sustainability?
The results presented in Table 7 indicate that there are significant differences between the cultural sustainability of museums with different numbers of visitors. An annual number of visitors fewer than 5000 has a negative influence on the cultural sustainability of a museum. A large number of visitors (above 30,000) positively influences the cultural sustainability, but in a lower measure compared with the interval of 5000-30,000. Therefore, we can conclude that the best performances regarding cultural sustainability are obtained by museums with an annual number of visitors of between 5000 and 30,000. These results are in line with previous theoretical findings. According to Pop and Borza [72], a very high number of visitors contributes to the financial prosperity of a museum (which helps it to take all the necessary measures for keeping the heritage in good conditions), but may also represent a risk for the proper conservation of the exposed objects, especially if the exhibiting area is small [73,74]. Conservation of cultural objects requires a constant climate and large visitor numbers may cause an imbalance in temperature and humidity within exhibitions [75]. Also, visitors are a source of hydrogen sulfide, which affects silver and copper objects [76]. On the other hand, museums with low numbers of visitors may encounter difficulties in attracting the financial resources they need for preventive conservation and restoration of their collections. Significant differences were also found regarding the cultural sustainability of the local, county, national, and regional museums. The average cultural sustainability is higher among county and national museums, while the local and regional relevance of collections proved to negatively influence the cultural sustainability of a museum. The better results of national museums compared with local museums can be attributed to the fact that the former succeed in attracting larger resources because of the historical and cultural value of their collections. However, the fact that county museums record an average cultural sustainability higher than regional museums is surprising. A possible explanation may be the fact that county museums are financed by county councils and national museums are usually financed by national authorities (e.g., the Ministry of Culture), while regional museums do not have an equivalent regional authority to whom they belong. Our research revealed that most of the regional museums included in the sample are financed by county or local councils. County councils seek to fulfill goals relevant to the well-being and interests of their county community members. On the other hand, regional museums hold heritage objects that are relevant to a broader area, not only to the county that finances them (a region includes more counties), and implicitly, their mission and goals refer to the entire region. Thus, it is likely that county authorities have less motivation to spend money on regional museums compared with county museums, simply because regional museums do not reflect the county values, identity, and history in the way that county museums do. The same explanation can be provided for justifying the higher cultural sustainability of county museums compared with national museums. While most of the national museums are financed by the Ministry of Culture or another ministry, in six cases, the respondents declared that they function under the authority of a county council.
Although we expected to see a higher level of cultural sustainability among the museums that belong to the NNRM, the ANOVA test proved to be insignificant in this case (p-value > 0.05), which means that this characteristic does not significantly influence the cultural sustainability of a museum.
On the basis of these preliminary results, the next step was to perform multiple linear regression in order to explore the relationship between DV and IVs [25]. Because there is a correlation between the exogenous variables (predictors) (see Table 6), we proposed two models to explain the link between the predictors and the DV, so that the multicollinearity effect can be avoided. Table 8 shows that the second model, which includes heritage exposure, effectiveness and performance, and openness to the public as significant predictors, achieved the highest value in the likelihood ratio (LR) test (67.356) and the highest R squared (0.33) of the two models. Although cultural sustainability is correlated with each of the four independent variables (Table 6), when their cumulative effect on cultural sustainability is analyzed, we note that environmental behavior becomes insignificant. This result can be explained by the fact that measures taken by museums to protect the natural environment, such as material recycling, the use of energy-efficient devices and systems, and encouraging an eco-friendly attitude among visitors and employees [77], influence cultural sustainability mainly through economy of financial resources, which allows for greater investment in the acquisition, preservation, and conservation of heritage. In the first model (Table 8), this effect is likely to have been taken over by the effectiveness and performance variable, given the significant positive correlation that exists between environmental behavior and effectiveness and performance (see Table 6). Consequently, the second hypothesis, that there is a positive relationship between cultural sustainability and environmental behavior, is rejected. Thus, in the case of Romanian museums, it is found that green practices adopted by museums do not have a significant effect on controlling the climatic conditions and avoiding the natural imbalances that could pose a threat to the safety of collections. 67.356 *** (df = 9) * Indicates significance at 10% level or less, ** significance at 5% level, *** significance at 1% level.
The first hypothesis, according to which cultural sustainability is positively related to effectiveness and performance, is accepted. Museums that optimize the ratio between their results (e.g., the number of events, the number of visitors, the revenue level) and the inputs they have used to achieve the results (e.g., the number of employees, the number of exhibited objects, the level of expenditure) will have a higher chance of accomplishing their mission of protecting the cultural capital.
The third and fourth hypotheses, according to which cultural sustainability is positively related to openness to the public and heritage exposure, are accepted as well. These findings show that the ability of museums to preserve, conserve, and research the cultural heritage can be enhanced by organizing attractive exhibitions inside and outside of the museum's walls, exhibiting a high proportion of the artefacts they possess, providing services and products according to visitors' needs and desires, offering participative and interactive educational programs, developing accessible and inclusive programs, collaborating with the community members for organizing various events, having a diversified structure of employees and volunteers so as to reflect the structure of the local community, and attracting new users and/or disadvantaged groups of people. Museums can offer attractive exhibitions and interactive educational programs by using modern technologies, such as audio-visual media, guided presentations, interactive navigation stations, simulation media, interactive films, 3D graphics, and virtual reality [78]. By performing these actions, museums will create the opportunity for a wider number of people to 'perceive, understand, and appreciate' the value of cultural heritage, the conservation of which is important for future generations [79].

Discussion
Museums are public institutions whose general mission is to serve society [80,81]. Given this mission, museums seek to have a positive impact on sustainable development. Financial constraints have forced museums to turn their attention toward becoming organizationally sustainable. According to Moldavanova [17], organizational sustainability includes both institutional survival and intergenerational sustainability, which is understood as the ability of a museum to fulfill its cultural mission in the long run. Beside the fact that sustainable management helps museums to prove their importance and to survive, our study showed that this approach also has a positive impact on museums' ability to achieve their cultural goals.
While most of the previous research presents the importance of cultural heritage in the process of sustainable development through its role in achieving social relevance and economic prosperity, influencing visitors to practice green activities, and developing their pro-environmental behavior [69,77], this paper adopts a less debated perspective, namely the examination of possible factors that can help museums to reach cultural sustainability by better accomplishing their goals related to the preservation, conservation, and research of cultural heritage. The factors included in the analysis were defined starting from the three classic dimensions of sustainability. The variable 'effectiveness and performance' was chosen for economic sustainability, 'heritage exposure' and 'openness to the public' were selected for social sustainability, and 'environmental behavior' was a factor associated with environmental sustainability. Using this approach, we aimed to evaluate the role of economic, social, and environmental sustainability in supporting the cultural mission of museums. Quantitative research was conducted to meet the aims of the study. The statistical results allowed us to accept three out of the four hypotheses referring to the positive connection between the DV and IVs.
The findings of the present study indicate that museums' effectiveness and performance, openness to the public, and heritage exposure have a positive impact on cultural sustainability. These findings are in line with the assertions of Loach et al. [4] and Errichiello and Micera [35], who hypothesized that economic and social dimensions of sustainability can be used by museums as tools for 'implementing cultural sustainability-oriented strategies'. Sustainable museums succeed in making better use of their resources, but at the same time, they have a higher financial capital available to collect, preserve, conserve, and research the cultural artefacts. Our results are also consistent with the findings of Pencarelli et al. [14], who emphasized that Italian museums are motivated to invest in social sustainability policies, because in this way, they can ensure their future. At the same time, socially responsible behavior allows museums to receive a higher level of public funding, which has a positive influence on their performance in terms of cultural heritage preservation [45].
Even though the correlation between environmental behavior and cultural sustainability proved to be significant, environmental behavior had no direct impact on museum cultural sustainability. Museum collections are not better preserved and conserved merely because they have an eco-friendly attitude and behavior. Therefore, the assumed impact of museum environmental behavior on protecting cultural heritage was not supported. The influence of pro-environmental behavior on cultural sustainability is rather indirect, through the economy of resources, which leads to higher effectiveness and, in this way, to cultural sustainability.
In conclusion, cultural heritage can be used as a resource for achieving economic, social, and environmental goals, but at the same time, our study has shown that some components of social and economic sustainability have the capacity to influence cultural sustainability within museums. Therefore, cultural sustainability has the role of both input and output in relation to the other pillars of sustainability, which reinforces the conclusions of previous studies that culture can be regarded as a fourth independent pillar of sustainability, equal to the economic, social, and environmental pillars [35,38], as illustrated in Figure 1.
a fourth independent pillar of sustainability, equal to the economic, social, and environmental pillars [35,38], as illustrated in Figure 1. In museums, culture, economy, society, and environment together create an ecosystem in order to achieve sustainable development. These structures are all resources/instruments and destinations/goals at different points in the cycle. Museums are financed by local communities and cultural vitality is the way in which museums reward the community for its effort. First, society invests money and resources in a museum. Second, the museum acquires, conserves, preserves, and researches cultural heritage artefacts. Third, the museum repays the community by using the heritage to create cultural vitality and economic development and to develop pro-environmental and socially responsible behaviors among its visitors ( Figure 2). The value created by the museum motivates authorities, sponsors, donors, and other stakeholders to continue to support it. The cycle is then repeated. In museums, culture, economy, society, and environment together create an ecosystem in order to achieve sustainable development. These structures are all resources/instruments and destinations/goals at different points in the cycle. Museums are financed by local communities and cultural vitality is the way in which museums reward the community for its effort. First, society invests money and resources in a museum. Second, the museum acquires, conserves, preserves, and researches cultural heritage artefacts. Third, the museum repays the community by using the heritage to create cultural vitality and economic development and to develop pro-environmental and socially responsible behaviors among its visitors ( Figure 2). The value created by the museum motivates authorities, sponsors, donors, and other stakeholders to continue to support it. The cycle is then repeated. However, it should be clarified that effectiveness and performance, openness to the public, and heritage exposure are not the only factors that have an influence on cultural sustainability. Guccio et al. [42] pointed out that the efficiency of cultural heritage preservation works is influenced by the professional characteristics of the specialists who take the decisions to carry out conservation work. The authors highlighted that specialized heritage authorities that belong to central government are less efficient in implementing conservation contracts than less specialized authorities. Errichiello and Micera [35] also examined the role of public-private partnerships and collaborations between cultural However, it should be clarified that effectiveness and performance, openness to the public, and heritage exposure are not the only factors that have an influence on cultural sustainability. Guccio et al. [42] pointed out that the efficiency of cultural heritage preservation works is influenced by the professional characteristics of the specialists who take the decisions to carry out conservation work. The authors highlighted that specialized heritage authorities that belong to central government are less efficient in implementing conservation contracts than less specialized authorities. Errichiello and Micera [35] also examined the role of public-private partnerships and collaborations between cultural organizations and local stakeholders in achieving cultural sustainability. Another important factor is the national support offered to cultural institutions for digitizing their heritage. As Fanea-Ivanovici [10] highlighted, in Romania, the lack of funds is the main reason for which the number of objects included in Europeana per number of inhabitants is one of the lowest in Europe.
Given this background and the results of our research, future studies should focus on exploring the influence of other possible factors on cultural sustainability in museums. Because market orientation, innovation, and the high value offered to customers have a positive impact on economic and social sustainability of museums [82], they might influence cultural sustainability as well. In particular, technological innovation was found to be a source of competitive advantage for museums [32] and, consequently, it could have a great impact on cultural sustainability as well. Other possible factors could include web-based services and digital tools [67], which were found to be relevant regressors of the museums' attractiveness [25]; financial structure and organizational size, which impact the level of performance in museums [45]; and retailing activities, which are a source of self-generated revenue [44].
In addition, the conclusions of the present study should be confirmed through research conducted in other countries and geographical areas with different cultural and environmental background. In Romania, the occurrence of natural hazards is low, which is why their negative effect on cultural heritage is almost missing, and implicitly, the measures taken by museums for environmental protection have proven to have an insignificant effect on the preservation of cultural heritage. However, the results could be different in countries that are frequently confronted with problems related to natural hazards caused by climate instabilities.
The results may also differ according to the level of cultural consumption that exists among various countries. Figure 3 illustrates the percentage of people of the age of 16 years or over who participated in cultural activities offered by European cultural sites (historical monuments, museums, art galleries, or archaeological sites) in 2015, by country of origin. heritage. However, the results could be different in countries that are frequently confronted with problems related to natural hazards caused by climate instabilities. The results may also differ according to the level of cultural consumption that exists among various countries. Figure 3 illustrates the percentage of people of the age of 16 years or over who participated in cultural activities offered by European cultural sites (historical monuments, museums, art galleries, or archaeological sites) in 2015, by country of origin.   While in EU countries, 43.40% of the sample population participated at least once in cultural activities in 2015, in Romania, this percentage is only 18.30%. The main reasons for non-participation in cultural activities offered by Romanian cultural sites were the following: financial reasons-20.1%, no interest-26%, none in the neighborhood-22.3%, and other-31.5% [84]. A very interesting aspect is that, compared with other European countries, Romania has the highest percentage of people who declared that they have not participated in cultural activities because of the fact that there 'is none in the neighbourhood' (22.3%). This means that Romanian cultural institutions should increase the number of exhibitions and activities organized in different locations in order to support the development of cultural sustainability.

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

No.
Statements Answer

ECONOMIC SUSTAINABILITY-Effectiveness and performance
1.
The ratio between the annual number of events organized by the museum and the average number of employees is high 2.
The ratio between the annual number of visitors registered by the museum and the average number of employees is high 3.
The ratio between the annual income earned by the museum and the average number of employees is high 4.
The average number of visitors registered by the museum per square meter of exposure area is high 5.
The ratio between the museum's revenue from the sale of tickets and the number of objects exhibited in the museum is high 6.
The ratio between the annual number of visitors and the museum's total expenditure is high 7.
The share of own revenues in the total revenue earned by the museum is high Sustainability 2019, 11 The museum where you work has: Less than 11 employees (very small museum) Between 11 and 20 employees (small museum) Between 21 and 50 employees (medium museum) Between 51 and 150 employees (large museum) More than 150 employees (very large museum) 9.
Does the museum have its own income and expenditure budget? Yes No (go to question 12) 10. The total revenues recorded by the museum in 2015 were: ……………….. lei. 11. How many percent are the museum's own revenues from total revenue? Under 6% Between 6% and 10% Between 11% and 20% Between 21% and 30% Between 31% and 40% Between 41% and 50% Between 51% and 60% Between 61% and 80% More than 80%

Was the museum in which you work open to visitors in 2015?
Yes Between 150,001 and 300,000 More than 300,000 14. The number of heritage objects owned by the museum at the end of 2015 was: ………… 15. What are the main issues affecting the sustainability of your museum (you can choose more options)?
Insufficient financial resources Lack of museum specialists The legislative system applicable to museums Lack of motivation among employees Excessive internal bureaucracy Excessive bureaucracy in relation to other institutions Reduced autonomy of the institution Insufficient storage and exposure space Others___________________________ 16. How long have you been working at the museum?