1. Introduction
The egg business in Taiwan has witnessed fast expansion, with strong and rising market demand for fresh egg products in Taiwan [
1]. This is shown by the growth of egg sales in Taiwan from 4% to 22% between 2015 and 2018 [
2]. Further, the egg consumption per capita among Taiwanese consumers is substantial, approximately 322 eggs per person per year [
3]. This implies that Taiwanese consumers consume almost one egg every day. There is a high demand for eggs because eggs are considered as one of the main staple products that can provide moderate calories (about 150 kcal per 100g) and high protein for diets [
4]. Not only are eggs a good source of nutrients and protein [
5,
6], but also eggs can play an important agent for the human body in receiving key nutraceutical elements for the dietary [
7,
8,
9,
10]. Thus, the global guideline advocates that eggs should be consumed on a regular basis as part of a healthy diet [
11]. In short, eggs are regarded as a vital element of the daily diets of all consumers [
11].
Since eggs played a prominent role in consumers’ daily lives [
12], the marketing strategies in supermarkets have attempted to promote many different attributes for fresh egg boxes to attract consumer attention [
13,
14]. Thus, it is imperative to identify consumer preference and their purchasing decision for fresh egg boxes. Previous studies [
15,
16,
17,
18,
19] had focused on freshness, visual features, and prices. However, more attributes (i.e., color, brand, animal welfare, traceability, organic, and nutrition label) of fresh eggs have been discussed in other countries, but not in Taiwan [
20,
21,
22,
23].
Consumer preferences of fresh eggs may have significant differences between nations [
24]. According to Li (2013) [
25], Chinese consumers prefer eggs with longer shelf life and the best-before-date information. Indonesian and Indian consumers exhibit a similar preference when it comes to purchase eggs. The findings show that these consumers pay more attention on price attribute [
11,
26]. Further, consumers in the United States (U.S.) prefer eggs with animal welfare and organic labels [
27,
28]. Additionally, the majority of European consumers are more likely to buy and pay extra for eggs with animal welfare labels [
29,
30]. Therefore, the attributes of egg products may have a significant impact on consumers in different countries, such as China, Indonesia, the U.S., and European countries.
In general, fresh eggs in supermarkets have a series of product attributes, such as brand (providing by farm brand and private brand, e.g., Carrefour), animal welfare (giving an animal-friendly environment to enhance animal welfare for laying hens, e.g., cage-free, etc.), traceability or traceable agricultural product (providing barcodes on egg products to assist consumers in tracing and tracking the product information), and certified agricultural standard (giving a certificate that guarantees eggs are fresh, clean, food safety, etc.) [
3,
14,
31,
32]. Do more product attributes embedded on fresh eggs mean more selling? Marketers believe that product attributes would potentially satisfy consumer preferences [
33]. Since more product attributes do not necessarily mean more positive influences on consumer preferences, sometimes too much information may impede decision-making and may even decrease the consumer’s desire to purchase [
34,
35]. Therefore, more in-depth investigation is required to determine which product attributes should be provided on fresh egg products to appropriately entice Taiwanese consumers to purchase.
Since there are a series of fresh egg attributes that will be examined and the willingness to pay (WTP) for fresh egg attributes is intended to be estimated, the choice experiments would be appropriate to implement in this study [
36]. When choice experiment studies are conducted, there may exist an unrealistic situation that may not be in accordance with the actual market situations [
37]. In addition to the survey design of choice experiments, the evidence of unrealistic choice sets is rare to be discussed. Since the design of choice sets for fresh egg attributes contains several unrealistic choice combinations, whether the unrealistic choice sets lead to a potential bias should be considered and discussed. Hereinafter, this study further tests the including and excluding the unrealistic choice sets to see if there is a potential bias that makes the estimator failure. Hence, this study will be able to provide more literature for the unrealistic choice sets in choice experiment research method.
4. Discussion
The present research used DCEs to ascertain which attributes may affect Taiwanese consumers’ decisions to buy fresh eggs in Taiwanese supermarkets, and five attributes of fresh eggs were considered: price, brand, color, traceability, and animal welfare. This researcher conducted an unrealistic choice experiment on CE to evaluate the impact of the unrealistic choice set on the estimated findings. Thus, this research will serve as a reference for including or excluding the unrealistic choice experiment for the CE design. Furthermore, this study also contributes significantly to the Taiwan government, egg business, and policymakers’ in terms of heterogeneous consumer preferences for egg attributes in Taiwanese supermarkets. Using the LCA method, this research found three unique groups of Taiwanese consumers, each with its own distinct set of preferences and WTP for fresh egg attributes, as well as distinct sociodemographic and behavioral traits.
As shown by the AIC, BIC, and Log-likelihood values in
Table 3, the data set without unrealistic options is more suitable than the data set with unrealistic choices as it has a greater Log-likelihood and lower AIC and BIC values [
79]. Moreover,
Table 3 also shows that 3 classes in the LCM gave the best fit since the marginal changes in AIC and BIC values between classes 3–7 are extremely small in comparison to the changes between classes 2 and 3. Additionally, the model’s estimated value for classes 4–7 have begun to degrade, resulting in an unstable AIC and BIC value. To summarize, the optimal number of classes for estimating LCM models is three.
Table 4 presented and contrasted the findings of LCM analysis on two distinct data types in order to determine the most appropriate data set for assisting the researchers in accurately analyzing and interpreting this study’s results. Further, this study will determine whether or not an unrealistic choice set has an effect on the LCM estimate outcome. The goodness of fit value generated by the LCM analysis may be evaluated [
79] to determine which data sets are more fitted and perform better with the model in this research. The AIC, BIC, and Log-likelihood values in
Table 4 suggest that excluding the unrealistic choice set model is more appropriate than excluding the unrealistic choice set model.
The results of attributes in
Table 4 show that most outcomes are similar to each other. The class shares of the excluding unrealistic choice set model reveal that the class-3 is the biggest consumer group with about 59% market share, while the middle and small groups of class share exhibit about 28% and 12%, respectively. It means that there roughly can present three types of consumer groups for fresh egg products in supermarkets. The attribute preferences of the largest consumer group show that they prefer farm brand, white-color eggs, traceability, and animal welfare. However, the middle-group consumers prefer lower prices, farm brand, brown-color eggs, traceability, and animal welfare; and the small-group consumers are particularly like the private brand of supermarkets, white-color eggs, and no traceability label. This implies that there still is a small consumer group that does not really prefer any attribute.
In addition, the results of the including unrealistic choice set model show that the largest consumer group with about 45% market share, while the middle and small groups of class share reveal about 40% and 15%, respectively. The composition of market shares in the including unrealistic choice set model is similar to the excluding unrealistic choice set model. If the traceability is compared in the small consumer group, then it received a different result. It implies that the smallest consumer group reveals a positive preference for traceability. Further, the results of attributes in the largest consumer group show that consumers prefer higher prices, farm brand, white-color eggs, and traceability. This is a bit of a contradictory outcome in price, since it implies that consumers will tend to buy more eggs if the price is higher. This outcome may reflect the cause of unrealistic choice sets. Moreover, if the unrealistic choice sets exist, it may lead to an expected outcome like this. Therefore, it is an important finding in this study that provides a good example if future studies adopt the CE method. However, the results of including unrealistic choice sets are not adopted as the final outcome in this study.
Following Equation (4),
Table 4 also shows how each social demographic variable and shopping background contribute to each class share. The largest consumer group of the class-3 is compared. Results of the excluding unrealistic choice set model show that higher age male consumers who usually purchase fresh eggs from non-hypermarkets are more likely to be in the smallest consumer group (i.e., the class-1). It also means that these consumers prefer attributes of private band, white-color eggs, and no-traceability when comparing to those who are in the largest consumer group. Although previous studies [
85,
86,
87] mentioned that the preference for white eggs is because it is cheaper than brown eggs, consumer preferences of white eggs in the class-1 do not link to the price attribute. It can be confirmed that some consumers may still prefer white eggs. The reason Taiwanese consumers prefer white eggs may correlate with the eggs price as usually, the price of white eggs in Taiwan tends to be cheaper than brown eggs. Consumers with lower education would prefer attributes of a lower price, farm brand, brown-color eggs, traceability, and animal welfare if compared to a reference group. Thus, it can be identified that younger female consumers with higher education who usually shopped at hypermarkets tend to be in the largest consumer group. This also corresponds to previous findings [
14,
31], that there is a potential market trend on-farm brand, traceability, and animal welfare for the majority of consumers.
The final WTP results will not contain an unrealistic option set model to avoid over-explaining the WTP findings of this study, even though the results may reflect every possible scenario. Thus, in order to account for the WTP findings in this study, the researcher concentrates only on excluding the unrealistic choice set model.
The WTP results of the excluding unrealistic choice set model reveal that only the middle consumer group of class-2 shows a significant level with a positive sign. This implies that consumers in the middle group (28.3% of market share) are more likely to pay more for these attributes than the price attribute; in other words, consumers are willing to pay more for the attributes of farm brand, brown-color eggs, traceability, and animal welfare. Particularly, consumers in the middle group would like to pay about 32.6 NT
$ (≈US
$ 1.16) more for farm brand labels if compared to the private brand label (i.e., Carrefour). This indicates that fresh eggs with farm brands are receiving more attention than the private brand in supermarkets. Further, regarding the egg-color attribute, consumers are willing to pay more about 32.5 NT
$ (≈US
$ 1.16) for brown-color eggs if compared to white eggs. This result also corresponds to previous studies [
15,
21] that consumers prefer to purchase brown eggs over white eggs due to the impression of health concerns and quality issues. However, this result represents the middle consumer group, so it is still not contradictory to the consumers who may prefer the white-color eggs in the small group of class-1.
In addition to the traceability attribute, consumers are willing to pay about 33.4 NT
$ (≈US
$ 1.19) for fresh egg products with traceability labels in supermarkets. Since consumers in Taiwan are more concerned about food-product originality and safety [
88], this study also corresponds to the argument of whether traceability is important in food product labeling. However, the animal welfare attribute presents a higher WTP than any other attribute. This implies that the animal welfare attribute is the most important among these attributes. Consumers in the middle group are willing to pay about 64.2 NT
$ (≈US
$ 2.29) for fresh eggs with animal welfare attributes in supermarkets. This finding also corresponds to a previous study [
13] that consumers do care for animal welfare. Therefore, this study confirms that there are potential markets for animal welfare, traceability, farm brand, and brown-color eggs in supermarkets in Taiwan.
Since the price attribute of the largest consumer group in
Table 4 did not show a significant level in the excluding unrealistic choice set model, it may lead to the WTP calculation of the largest consumer group in
Table 6 having not shown a significant level in the excluding unrealistic choice set model. This implies that these attributes in the largest consumer group are not identified in the WTP calculations. In other words, consumers in the largest group may focus on other attributes as their preferences. However, regardless of the WTP calculations, consumers in the largest consumer group still care about farm brand, white-color eggs, traceability, and animal welfare attributes.
5. Conclusions
Fresh egg products in supermarkets are getting more diversified by promoting different qualities in eggs, such as animal welfare, traceability, farm brand, color of eggs, etc. Since eggs are one of the fundamental elements for daily diet and consumers do care about what they eat, this study attempts to ascertain consumer preferences via the WTP and market segmentations. The CE method was utilized to estimate the market segmentations as well as the most important attributes that may influence consumer preferences. Further, this study also compares the results of including and excluding the unrealistic choice sets in the estimation of the LCM model. According to the values of the goodness of fit, the excluding unrealistic choice set model reveals better goodness of fit than the including unrealistic choice set model. Indeed, the overall outcomes of these two models present differently. Moreover, it is strongly recommended to other studies if the CE method with the choice set situation is adopted; the existing unrealistic choice sets should pay extra attention. With the indication of AIC, BIC, and Log Likelihood, this study only adopts the outcomes of the excluding unrealistic choice set model.
The findings in this research contribute to a better understanding of what motivates Taiwanese consumers to purchase fresh eggs in supermarkets. Among the major attributes, i.e., animal welfare, traceability, farm brand, and brown-color eggs, each attribute reveals a positive preference for certain segments of Taiwanese consumers. Especially, consumers who prefer animal welfare eggs are willing to pay up to about 64.2 NT$ (≈US$ 2.29), which is about twice above from the WTPs of other attributes, i.e., traceability, farm brand, and brown-color eggs. This presents that the animal welfare factor is a hot topic in supermarkets now. The overall results of this study convey strong signals to the egg industry, stakeholders, government, and policymakers about the market potential for brown-color egg, animal welfare, traceability, and farm brand attributes in supermarkets.
Several limitations in this study should be addressed. First, only five attributes are considered in this study, while other potential factors (i.e., nutritional facts, Halal, freshness, etc.) are omitted. Second, this study only focuses on supermarkets in Taiwan, while other major markets, such as traditional markets, are not considered in this study. In order to provide more comprehensive information, a further examination is needed, so government and policymakers would be able to make the relevant policies that encompass the entire consumer demand.