Research into the Relative Influences of Spouses Doing Housework, Family decision-making, and Physical and Mental Health on Chinese Family Marital Satisfaction

: Marriage is one of the closest and longest relationships in people’s lives. However, not everyone finds happiness in a marital relationship. In recent years, the rapid development of the social economy and the rapid transformation of the social structure have impacted on the traditional marriage relationship in China. The stability of the modern family structure has encountered severe challenges and the divorce rate has increased year by year. This makes research into the factors that influence marital satisfaction an important topic. We used data from the China General Social Survey (CGSS) in 2017 to construct a structural equation model to study the influences of spouse doing housework (SDH), family decision-making (FDM) and physical and mental health (PMH) on Chinese family marital satisfaction (MS). Our results show that SDH has a positive effect on MS, FDM has a negative effect on MS, and PMH has a positive effect on MS. SDH and FDM affect MS in combination, as do SDH and PMH. PMH has the greatest impact on MS, followed by SDH, and FDM has the weakest relative impact on MS. This research has important practical significance for society and suggests ways in which a “harmonious family” could be promoted by motivating society to promote and support a good family style, and so to improve MS for married couples.


Introduction
Marriage is a unique institution that responds to a human need. It helps people to find fulfillment and meaning in life and acts as a source of individual happiness [1]. The marriage relationship is often one of the closest and longest relationships in people lives [2]. Many couples see marriage as a sacred covenant that leads to family formation, and the stability of the family structure is then dependent on the quality of the couple's relationship [3]. However, not everyone finds happiness in a marital relationship [2]. In the context of rising commodity and housing prices, money has begun to have an overwhelming impact on family happiness. The "Marriage and Family Happiness Survey in the year of 2016", conducted as part of the "China Well-being Index in 2016" shows that 56.9% of people think that love cannot be measured by money, 36.7% of people think that love is priceless, and 1.8% of people think that love is worthless [4].
Marriage traditions such as blind dates, engagements, dowry gifts, and marriage itself are common in society, and some local marriage customs have formed, such as "high dowry and luxury dowry once again sweeping China's rural areas" [5]. In recent years, the increasing divorce rate has become a topic of social concern. The "Civil Affairs Development Statistical Bulletin in 2019" shows that there were 4.701 million couples who went through divorce procedures nationwide, an increase of 5.4% over the previous year. And in 2019, the divorce rate was 3.4 per thousand, an increase of 0.2 thousand points over the previous year. The marriage rate in China is declining year by year. The marriage rate in my country was 6.6 marriages per thousand people in 2019, a decrease of 0.7 from the previous year. Some scholars have pointed out that the increase in the divorce rate reflects a weakening of marital stability in our country, and that the quality of marriages must be improved to make them more stabile and to reduce the divorce rate [6].
The "Marriage Law" was enacted to replace the "Constitution" in 1950, following the formation of the People's Republic of China (PRC). This act advocates marriage freedom and opposes marriage oppression. Since the reform and opening up of the PRC in 1978, economic development, cultural exchanges, and improved quality of life have fundamentally changed people's concept of marriage. It is now rare for parents to arrange their children's marriages, and laissez-faire marriages are becoming more common. Marriage freedom has been taken to the extreme, resulting in flash marriages and divorces, trial marriages, temporary couples, wife swaps and one-night stands [7].
The rapid development of the social economy and the rapid transformation of the social structure have impacted the traditional marriage relationship in China. The stability of the modern family structure has encountered severe challenges and the divorce rate has increased year by year. This has made research into marital satisfaction (MS) an important topic in family sociology. Marital satisfaction and its relation to different aspects of human life has been well researched [8], but the effects of spouse doing housework (SDH), family decision-making (FDM) and physical and mental health (PMH) remain important topics of study. This research has important practical significance for exploring the mechanisms that influence family satisfaction in China.

Literature review
The family is a fundamental component of society, and marital satisfaction is the main characteristic of a healthy family [9]. Marriage is a specific relationship between individual people in human society, and is a product of the stage of development that human society has reached. Marriage has become an indispensable part of human social life [10]. Existing studies on MS have focused on the influences of social psychology [11], household registration matching, gender roles and marital life satisfaction [12], the effect of mating patterns [13], analysis of current rural MS [14], educational marriage matching [15], cognitive emotion regulation strategies and MS of the elderly in response to negative events between husband and wife [16], the effect of beauty [17], the effect of income [18], the effect of family resilience [19], gender, race and adult attachment [20], and religiousness [21]. However, there have been relatively few studies into the effects of spouse doing housework, family decisionmaking, and physical and mental health on MS.
MS has typically been constructed as a multifactorial construct, including factors such as global distress, affective communication, problem-solving communication, time together, finances, sexuality, role orientation, children, child-rearing conflict, dyadic satisfaction cluster and child issues cluster [22]. Couples' perceptions of MS vary with individual characteristics such as gender, age and personality, and with factors such as marriage matching, family resources, and marriage and childbearing patterns [17]. There are differences in MS among couples, according to their age proximity, marriage age, gender, occupation, educational background, marital status (whether or not they were previously married), income, health status, view of marriage, view of housework, time spent communicating between husband and wife, and number of children [23]. Some scholars use family questionnaire data from the China General Social Survey (CGSS2006) from 2006 with a structural equation model to construct exogenous variables from two dimensions of housework and family decision-making. For example, preparing dinner, washing clothes, and cleaning the house may constitute the housework activity dimension; the upbringing of children, the support of one's own parents, the distribution of household expenditure, and the purchase of high-priced household items may constitute the family decision-making dimension. MS is a dependent variable, i.e., an endogenous variable in the structural equation model, which can be represented by overall satisfaction and the possibility of mate substitution [24]. Physical and mental factors also have an impact on MS, and sound physical and mental health has a positive effect on MS.

The effect of SDH on MS
Family work refers to the day-to-day work families do to care for each other's physical and emotional needs. Differences exist between the types of household tasks that men stereotypically perform and the types of tasks that women stereotypically perform. Doing household chores is only part of the family work construct, and family work also includes tasks directly and indirectly associated with child rearing and relationship development [25]. Researchers used social exchange theory and equity theory to systematically analyze the function of the household division of labor. Social exchange theory states that partners in a marriage will strive to maximize the benefits, and will feel more satisfied with a relationship in which the benefits outweigh the costs. According to this theory, when respondents undertake fewer household chores and their spouses undertake more, the respondents' MS is high. Equity theory states that people become angered when they find themselves in an unequal relationship. Too much access or too much exploitation means inequality, because of people's dissatisfaction with the relationship. So the more equitable a husband and wife feel about their division of housework, the higher their MS [26]. The division of housework in a marriage can ensure that one spouse has better conditions to accumulate the human capital required by the labor market, thereby obtaining more wealth [27]. Uneven sharing of family responsibilities after marriage, lack of mutual understanding and mutual help between husband and wife, will inevitably lead to a decrease in the marital happiness index for at least one party, thereby affecting or even changing the marital status [28]. A more complete model of the division of family work that includes the degree of involvement of a father in child-rearing tasks can be used to explore how this influences father-child relationship quality and satisfaction with family work, and to test the effect that this has on husband's and wives' perceptions of martial quality. Both husbands and wives report higher marital quality when they are more satisfied with the division of labor [25]. Guided by family systems theory, a dyadic model explores the effect of husband's participation in family work and child rearing on both husbands' and wives' martial quality. The more wives perceived that husbands were engaged in routine family work tasks, the better the relationship was perceived to be by both partners. However, when husbands reported increased engagement in routine family work, both wives and husbands reported lower martial quality [25]. Some studies have shown that husbands sharing housework and participating more in housework can significantly improve MS [29].
H1: Spouse doing housework (SDH) has a positive effect on marital satisfaction (MS).

The effect of FDM on MS
The relationship between MS and the attitudes held by each marriage partner (liberal, egalitarian attitudes vs. traditional, conservative attitudes) is not clear. Spouses sometimes foster multiple roles and androgynous skills, which are consistent with the changing needs of marriage [30]. Resource theory proposes that each spouse's decision-making power varies directly with the amount and value of the resources that he or she provides to the marriage or to the other spouse. Resources are defined as anything that one spouse makes available to the other spouse to help them to satisfy their needs or attain their goals. Social exchange theory focuses on the exchange value of the spouses outside the marriage and argues that a spouse who has more accessible alternatives to their present marriage has more marital power than their spouse does. According to normative integration theory of the family, a couple's consensus over how martial power is distributed is an important factor for marital harmony, regardless of whether the marriage is egalitarian or not [31].
MS can affect children's development, well-being, biological functioning, academic performance, social skills, and relationships. MS is a subjective and multidimensional concept, and partners who perceive higher benefits and lower costs in their marriage are more satisfied [9]. Resource theory argues that a couple's relative resources determine their relative power. The spouse with the resource advantage has more power than the other in making family decisions. In a cultural context, resource theory states that the distribution of power between husband and wife does not depend on a single comparative resource, but on a combination of two factors: the comparative resources of husband and wife, and the norm of marital power that prevails in the culture or subculture that surrounds the marriage. According to this theory, there is an interaction between cultural norms and relative resources [32]. Studies have shown that when one or both spouses, or a family member outside the marriage, has fixed personal characteristics, then a spouse's family decision-making power can have a significant impact on MS [18].
H2: Family decision-making (FDM) has a positive effect on marital satisfaction (MS).

The effect of PMH on MS
MS refers to a couple's subjective feelings about their marital situation [23]. MS is a mental state that reflects a person's perception of the costs and benefits of their marriage. People feel satisfied when they feel that their marriage brings them higher benefits and lower costs [33]. The happiness of a marriage is a dynamic psychological experience. New stimuli, new changes, and new life may make those in it feel renewed, while pressure, dullness, and tediousness may become the final straw that breaks the camel's back in an already strained marriage [34]. This suggests that the family now functions to provide personal private satisfaction to make life meaningful and rewarding for adults who live in families. The family, and particularly marriage, can provide rewards in terms of life satisfaction, mental well-being, mental health and physical health [35].
MS is important for health and well-being [36]. Walker et al., 2013 measured satisfaction from different social relationships, including between confidants, friends, children, and other relatives and related these to levels of physical and psychological well-being. The results indicated that an individual's own depressive symptoms were related to their levels of MS, whereby higher scores on the depression scale were associated with lower MS scores. Being married, particularly in a satisfying marriage, is thought protect health and well-being. While relationships can also support emotional and physical well-being, they can also have potential negative impacts on health and well-being if characterized by dissatisfaction or dysfunction. Therefore, although MS or the quality of the relationship is particularly important for health and well-being, the role of a spouse in the context of other social relationships is also important [36].
Low MS is related to anxiety [37]. Few studies have demonstrated that higher MS results in lower depression levels, although some studies have reported that martial discontent can sometimes be inferred from signs of depression, and a recent study reported that MS negatively affects depression [38]. MS has an important impact on marital stability and on the physical and mental health of family members [24]. Some studies have suggested that a happy marriage may make people physically and mentally healthy, and that the physical and mental harm caused by an unfortunate marriage to both parties and the family is irreparable [39]. Whether or not a marriage is happy depends on psychological factors. Negative psychological factors, such as pain, anxiety, depression and other longterm effects, can create a persistent stress in an individual's heart, which can eventually destroy the body's immune system and neuroendocrine balance, and damage their physical health [40]. A decline in a spouse's physical health may impose a financial burden on a marriage, and the resulting family labor deficit may increase the psychological burdens for both spouses. A spouse's depression and anger can contribute to negative marital events that affect MS [41]. Increases in depressive symptoms have been related to decreases in MS [42]. Depression is an important component of mental health [43].
It is necessary to find an efficient psychological intervention that can be used to improve both marital functions and marital relationships. Several factors contribute to the quality of a marital relationship, including emotional expression, family of origin dynamics for each of the spouses, verbal communication, problem solving abilities, relationship skills, infidelity, sexual relationships, satisfaction in love, mutual respect, the duration of the marriage, trust and loyalty, and any mental problems faced by either of the spouses [44]. MS is the degree to which a spouse perceives that their partner meets their needs and desires [45]. MS is a general term that captures a spouse's subjective evaluation of, or attitude towards, the relationship between themselves and their partner; it is an important parameter for assessing the emotions of married people [38].
H3: Physical and mental health (PMH) has a positive effect on MS.

Data Sources
The data in this article come from the 2017 China General Social Survey (CGSS). The CGSS is the earliest national, comprehensive and continuous academic survey undertaken in my country [46]. The project was hosted by the China Survey and Data Center at Renmin University of China, and surveyed more than 10,000 households across the country [47]. The survey covered 28 provinces, municipalities and autonomous regions using multi-stage stratified PPS random sampling [29]. These data comprehensively reflect the living conditions of Chinese people [47]. This paper selected 2555 samples from the survey results as our original data, covering different cohabitation and marriage experiences. The samples were divided into six types of cohabitation and marriage experience: cohabitation, first marriage with a spouse, remarriage with a spouse, separated but not divorced, divorced, and widowed. We used these data to identify the factors to be used in our analysis: current physical health (CH), the degree of depression experienced over the four weeks before the survey (DP), the frequency with which one spouse made dinner (SD), the frequency with which one spouse did laundry (SL), the frequency with which one spouse cleaned the house (SC), the distribution of child care responsibilities between the partners (CR), and the distribution of household expenditure (HE). We analyzed the effect of these factors on MS and the mechanism for the effect (Table 1).

Exploratory factor analysis
We used principle component analysis to perform an exploratory factor analysis (EFA) on CH, DP, SD, SL, SC, CR, and HE and identified principle components with an eigenvalue greater than 1.0 as influencing factors [48]. This resulted in seven influencing factors, which explained 76.790% of the total variance in MS (cutoff value 60%) [48].

Structural Equation Modeling
We repeated our EFA for a different sample from the survey results (with the same sample size as for the initial EFA, N = 2555) to verify the factor structure identified in the initial EFA analysis, assuming all the factors to be independent [48]. The structural equation model (SEM) was used to analyze relationships between the influencing factors and the dependent variable, such as MS [49].
Where X and Y refer to the vector quality of exogenous and endogenous indicators, respectively, Λ and Λ are factor-loading matrix, B represents the relationship between endogenous latent variables on exogenous latent variables, and the , , ς refer to the residual item.
I used IBM SPSS Statistics 20 to compute the reliability, validity, principal component analysis, and the factor-loading for each identified influencing factor, as well as the Pearson correlation coefficients for the influencing factors. The structural equation model was implemented in Amos21 to analyze the relationships between MS and the influencing factors.

Correlation analysis
The correlations between MS and the influencing factors are shown in Table 2. the correlations between MS and variables SD, SL, SC, CR, HE, CH, DP and MS are significant, and have Pearson correlation coefficients between -0.810 and 0.836.

Results of exploratory factor analysis
The common factor variance after exploratory factor analysis is shown in Table 3. The average variance extracted (AVE) of all indicators is between 0.693 and 0.876. So all the AVE scores of the six factors exceeded the cutoff value of 0.5, demonstrating sufficient convergent validity [48]. The specific dimension division results are shown in Table 4. SD, SL, and SC are divided into one dimension, representing the spouse doing housework (SDH), and the indicators corresponding to this dimension are used to study the impact of the spouse's contribution and responsibility to the family on MS (MS). CR and HE constitute the family decision-making (FDM) dimension, and the corresponding indicators of this dimension are used to study the influence of FDM power on MS. CH and DP represent physical and mental health (PMH) dimensions, which are used to study the effects of PMH on MS.

Reliability test
A SEM was constructed for MS from SDH, FDM and PMH ( Figure 2 [50]. CMIN/DF ( ) is less than 5, showing that the model fitting effect is also good [51] after adjustment for the sample size [52]. It may not be sufficient to determine the fit for the measurement model only using the chisquared test statistics [53]. I calculated other model fit indices and found that these also showed the model to be acceptable. So these metrics show that the indices calculated from the model are good. The absolute and relative fitting indices indicate that the internal structure of the SEM is sound, and the parsimonious fitting index indicates that the external structure of the model is also sound.

Confirmatory factor analysis
The regression weights and standardized regression weights for the default model are shown in Notes: *** means significant at 0.001 level; ** means significant at 0.005 level.

Path analysis
According to the latent variables of SDH, FDM and PMH, a structural equation model of the influencing factors of marital satisfaction was constructed ( Figure 2, Table 8).
The latent variables of SDH and PMH have 0.001 significance for MS. The influence value for the path between the latent variable SDH and MS is 0.112, so the result supports the H1, such as SDH has a positive effect on MS, which is significant at the 0.001 level. The path effect value between the latent variable FDM and MS is -0.062, so the result un-supports H2, such as FDM has a negative effect on MS, which is significant at the 0.001 level. The influence value for the path between the latent variable PMH and MS is -0.262, so the result supports the H3, such as PMH has a positive effect on MS, which is significant at the 0.05 level.  Notes: *** means significant at 0.001 level; ** means significant at 0.005 level.
The Pearson correlation coefficient between SDH and FDM is -0.143, and both of these affect MS and are significant at the 0.001 level. The Pearson correlation coefficient between SDH and PMH is -0.077, and both of these affect MS and are significant at the 0.005 level. The Pearson correlation coefficient between MS and the combined effects of FDM and PMH was -0.004, and the correlation is not significant (Table 9). There is an overall influence effect that is equal to the direct influence effect between MS and SDH, FDM and PMH, and there is no indirect influence effect (Table 10).

Discussion
There is a positive correlation between SDH and MS. The correlation coefficients between SD, SL, SC and MS are 0.107, 0.121, 0.142, and are significant at the 0.01 level. The SEM shows that the SDH has a significant positive correlation with MS, so the SDH affects MS, and the degree of influence is 0.112. The complementarity hypothesis holds that in a married family, when the income gap between husband and wife is large, the spouse with the lower income leaves the workforce to take care of the family full-time, and the spouse with the higher income works to support the family, realizing a specialized division of housework and improving the family income and quality of life [47].
There is a negative correlation between FDM and MS. For example, the correlation coefficients between CR, HE and MS are -0.051, -0.050, and are significant at the 0.05 level. The SEM shows that there is a relationship between FDM and MS, with an impact effect of -0.062. This implies that an uneven distribution of childcare and household expenditure leads to low MS. Following resource theory, economists point to the fact that married couples share some basic living expenses, which reduces the overall family expenditure and so increases the sense of well-being. If one spouse undertakes a greater share of the expenditure then this can reduce his/her perception of MS [47]. The theory of relative love and need states that each spouse contributes resources to the marriage and receives rewards from their spouse. The exchange may not be balanced and one spouse may exchange more than the other, making one spouse more dependent on the marriage relationship than the other, and thereby make them more likely to conform to their spouse's preferences. According to this interpretation, a spouse who endows the marriage relationship and the resources provided by their spouse with a higher value is in a weak power position, while a spouse who pays affection may control and utilize their resources more freely and effectively, and thus gain an advantageous power position. The strongest influence on the power relationship within a marriage is how much a couple love and need each other [32]. Family systems theory makes four important propositions about family functioning. First, a family is a unit of organized, interdependent individuals. The individuals are best understood in the context of this whole unit, where the functioning of the individuals is related to the individuals themselves and to the complex system of behaviors between members of the system. Thus, individual contributions to martial quality may be best understood by considering both spouses' perceptions of their martial union, and by considering other and shared activities, such as household labor and child rearing within the same family system. The interdependent nature of the family system suggests that a husband's experiences within the family system influence both his and his wife's perceptions, and vice versa. Family roles and expectations can also create meaning in family relationships. The way spouses work within interconnected subsystems may influence their perceptions of the marital relationship [25].
There was a positive correlation between PMH and MS, and the correlation coefficients between CH, DP and MS were -0.153, -0.180, and were significant at the 0.01 level. Structural equation modeling showed that the direct effect of PMH on MS was -0.262, and was significant at the 0.001 level. This means that the healthier the body and the healthier the mind, the higher the MS, and vice versa. This is because marriage has a "selection effect" and a "protective effect". The selection effect refers to the fact that individuals with certain characteristics can persuade their partners to get married and become husband and wife, and the spouses' perception of mutual satisfaction then increases in their married life. Marriage itself is conducive to the physical and mental health of both spouses, and enables people to more easily cope with the challenges of life, provides emotional and financial support, and improve MS [54].
The relationship between SDH and FDM affects MS. Our results show that there is a negative correlation between SDH and FDM. This means that a happier marriage does not necessarily follow from one spouse undertaking a disproportionate share of housework. The spouse must also be properly involved in FDM, such as the upbringing of children and the distribution of household expenses. A spouse's share of the housework and their physical and mental health jointly affect MS. Undertaking a disproportionately high share of housework can have a positive impact on a spouse's physical and mental health. When one spouse undertakes trivial chores such as cooking, laundry and cleaning, they create space and time for more complicated housework, which can effectively relieve the physical and mental fatigue caused by the trivial housework, and this can effectively promote perceptions of MS. Family decision making is associated with better physical and mental health, however the correlation between FDM and PMH is weak and there is no significant correlation between MS and either FDM or PMH. The actor-partner interdependence model considers interactive influences between husband and wife [55], and these can be seen in the correlations between SDH, FDM and PMH.
The SEM shows that physical and mental health have the greatest impact on MS, followed by spouse doing housework, and that family decision-making has the least impact on MS. Partners in a marriage will strive to maximize the benefits, and a relationship in which the benefits outweigh the costs will make them feel more satisfied. The more equitable the exchange of resources is in a relationship, the more satisfying the relationship is [56].

Limitations
Previous research shows that MS has a U-shaped relationship with increasing marriage age. This study did not explore the homogeneity and heterogeneity of factors that influence MS for marriages of different lengths. We did not differentiate between the influencing factors for MS for the different types of cohabiting couples: first marriage with a spouse, remarriage with a spouse, separated but not divorced, divorced, and widowed, were all considered as cohabitation. To differentiate between the different influences on MS for these different situations, and the different pathways for the influences, should be explored in future research. This paper does not explore the effects of individual characteristics such as age, income, education level, or occupation on MS. MS itself has an impact on the physical and mental health of both spouses, and there may be a two-way relationship between physical and mental health and MS, which should be looked at in further research.

The government should introduce policies to effectively improve people's MS
The government should call on all of society to build a "harmonious family" and should reward families with excellent MS. This would effectively motivate society to support a good family style, and improve the MS of husbands and wives. The government has already established a beneficial medical policy to effectively protect the physical and mental health of married couples, and should encourage men to actively participate in household chore. Finally, the government should improve the family's ability to adapt to changes in living conditions, challenges, and pressures by providing adequate social support to improve family resilience.

Both husband and wife should work hard to pursue the happy marriage
The harmony of marriage should be reinforced daily by small actions such as saying "thank-you". Seemingly trivial issues should not be ignored and spouses should appreciate each other rather than taking each other's actions and support for granted. When a spouse does laundry and cleans the house, the other spouse should say "thank you" and "hard work" to express respect and affirmation. Spouses should not accuse their partners of doing bad things, should fully trust each other, should not compete for "leadership" in the family, should maintain an attitude of consultation and communication when making family decisions, and should give each other respect and freedom, and not impose personal preferences on each other or force each other to change or make concessions [39].

Both husband and wife should reduce their marital expectations
In some cases, both husband and wife should cease to pursue an unrealistic ideal of married life. Spouses should improve their psychological cognitive flexibility, which itself contributes to MS, and which also promotes physical and mental health, which further contribute to MS for both spouses. When there is a conflict between family decisionmaking and housework, MS can be improved if a husband and wife empathize, exchange roles, re-adjust their positions, and consider each other more appropriately [57].

Both husband and wife timely feedback their feelings and emotions in the marriage
Feedback between spouses can lead to more equal roles in the marriage in terms of housework and family decisionmaking, which helps husband and wife to achieve a higher degree of consistency, inclusiveness and complementarity in their married life, thereby reducing the cost of the marriage to both spouses. Differences between family cultures and the personalities of both spouses may improve the mental and physical health of both spouses [55]. Both spouses should participate equally in household labor, in supporting the elderly, and educating children. Family decision-making should follow discussions between spouses and not be arbitrary, and both parties should be considered in every decision.

Conclusions
SDH has a positive effect on MS. SDH can promote social division of labor and labor specialization, which is conducive to resource sharing. FDM can have a negative effect on MS. The greater the disparity in the distribution of household income between husband and wife, and the less equal their roles are in raising their children, the lower their MS is likely to be. The equal sharing of responsibilities between husband and wife promotes high MS. PMH has a positive effect on MS, and the "selection effect" and "protection effect" indicate a positive correlation between PMH and MS. SDH and FDM affect MS in combination, which shows that the more housework a spouse does, the happier the marriage will be, provided that the spouse participates equally in FDM. SDH and PMH affect MS in combination. The more housework a spouse does, the more positive the impact on the spouse's PMH. The influence of FDM on PMH is strong and therefore, although FDM negatively affects MS, this is balanced somewhat by the positive effect of PMH on MS, and the combined influence of FDM and PMH is therefore relatively weak. We found no significant correlation to show that FDM and PMH jointly affect MS. PMH has the greatest impact on MS, followed by doing SDH, and FDM has the least impact on MS. A deep understanding of fairness is required for high MS.

Declaration of conflicting Interests
The author declared no potential conflicts of interest with respect to the research, authorship, and、or publication of this article.