There are three main employment modes for the disabled in China: centralized employment, proportional employment and individual employment. Like other members of society, persons with disabilities also have the need for social interaction and have equal rights to work and development [2]. Previous studies have also shown that people employed in the open labor market have a higher quality of life than those employed in protective workshops [23]. Compared with centralized employment in welfare enterprises and individual job selection, proportional employment (employment quota system) can better protect the rights of the disabled to develop and promote social communication. In recent years, the Chinese government’s policy system has also been gradually weakening its emphasis on centralized employment and emphasizing instead market-oriented models such as proportional decentralized employment [24].

China’s employment quota system dates back to 1990. The 1990 law on the protection of the disabled mentions that employers should arrange the employment of the disabled according to a certain proportion. However, due to weak supervision, the proportional employment system has been ineffective. In September 2015, the Chinese government launched the Management Regulation of the Collection and Use of Employment Security Fund for the Disabled, redefining the employment quota for the disabled in enterprises and strengthening the collection of fines from enterprises that fail to meet the quota. According to the new regulation, enterprises with more than 20 employees are obliged to provide jobs for the disabled according to the quota, which ranges from 1.5% to 2% in different provinces. If the enterprises fail to achieve the quota, they must pay the employment security fund for the disabled based on the average compensation of on-the-job employees. Conversely, enterprises that have overfulfilled the employment task can be rewarded with government subsidies.

According to our calculation, the employees’ average monthly compensation of Chinese Listed Companies in 2021 is about 16,000 yuan; that is to say, compared with other countries’ implementation of the employment quota system for the disabled, the quota required by the Chinese government is relatively low (e.g., the quota set by Germany is 6%, and the quota set by Austria is 4%) but the amount of employment security fund for the disabled is relatively high (e.g., Japan requires employers to pay a monthly amount of 50,000 yen per person short of their levy quotas if they are unable to achieve the quotas, equivalent to 2555 yuan). In the following four years, in order to reduce the economic pressure of enterprises, the Chinese government reduced the maximum amount of employment security fund for the disabled and in 2020 adopted the method of phased collection. However, the overall model of the employment quota system has not changed greatly.

In addition to employment security fund for the disabled, the Chinese government has also adopted tax relief for enterprises that provide jobs for the disabled. The wages paid to disabled employees can be 100% added and deducted when paying enterprise income tax. Disabled employees are also exempted from individual income tax, indirectly reducing an enterprise’s labor cost.

Studies have shown that employers believe the biggest challenge in recruiting people with disabilities is the worry that they cannot complete their work effectively [25]. This concern is mainly based on three considerations. First, the physical and mental conditions of disabled employees may lead to their higher absenteeism rate, shorter working hours and lower productivity [26]. Second, employers are worried that the disabled cannot complete manual work and desk work at the same time [27,28]. Third, sometimes the disabled cannot effectively use the equipment provided in the workplace [29], which will affect the communication between the disabled and other employees. Employers need more accurate and practical information, especially on the specific impact of different types of disability on productivity, in order to eliminate their preconceptions about persons with disabilities and concerns about the productivity.

In fact, as long as the work arrangement is reasonable, disability does not necessarily reduce work efficiency. For example, case studies have shown that deaf employees are fully competent for work on the production and assembly line [10]. Employees with physical disabilities are no different from other people in speech expression and can be fully competent for customer service [30]. Moreover, due to the difficulty of job hunting, disabled employees will cherish their work. They tend to be more loyal, punctual [12], work longer and have a lower turnover rate [13,14,15]. In addition, the construction of barrier-free facilities is the most important way to eliminate “environmental barriers” in the workplace and improve the labor productivity of disabled employees [31].

The core issue of employee diversity discussion is the diversification effect brought by differences among employees. The differences among employees will affect their way of thinking and work attitude, impacting firm performance. For the impact of employee diversity on firm performance, information decision theory (Williams et al., 1998) [32] and social classification theory (Turner et al., 1987) [33] give two opposite explanations.

Information decision theory believes that diversity plays a positive role in promoting firm performance. When there are great differences within the group, the knowledge and skills brought by diversity can fully increase the cognitive resources of the group and improve firm performance [34]. These documents mainly focus on the gender composition of corporate governance. In the context of our study, employees with a disability contribute new creative and other skills to the work environment and their role [19,20,35]. Disabled employees can think from the perspective of different customer groups and make the company’s customer base more diversified [14,18,36]. In addition, the company’s inclusion of disabled groups can make employees feel social altruism and personal satisfaction [16], creating a more inclusive workplace culture and thereby strengthening a company’s overall workforce [5,18,20,37,38].

Social categorization theory believes that diversity has a negative effect on firm performance because diversity may lead to the decrease of team cooperation and the efficiency of the decision-making process [39]. In the context of the including disabled employees in the workforce, people are often reluctant to interact with those with mental health problems and equate mental illness with a tendency towards violence [40]. Similarly, employees have negative feedback on people with communication barriers, believing that they do not have enough ability in the fast communication environment and will affect the overall work performance of the team [41].

Furthermore, the literature shows that the specific impact of diversity on firm performance may vary depending on the environment in which the company operates [10]. For example, the study conducted by Duppati et al. (2020) shows that the market performance of female directors is better in countries that support gender equality [42]. The results of these studies show the positive effects of diversity to be stronger under a climate of supportive diversity conditions.

With the rise of the concept of corporate social responsibility, CSR is gradually regarded by companies as an important strategic resource in improving financial performance. Corporates’ fulfillment and disclosure of social responsibility can help establish a good reputation and corporate image [43,44]. Especially since the outbreak of COVID-19, investors and the public have paid more attention to the sustainable development ability of enterprises and their long-term commitment to fulfilling their social responsibilities [45]. From the perspective of risk management, continuous CSR behavior will bring positive moral capital, reduce the negative evaluation of consumers after negative events and play a buffer role in the event of crisis [46]. In addition, CSR is often regarded as an important way to obtain political connection and develop resources [47,48], playing a positive role in promoting firm performance.

Although the topic of CSR has a long history, few studies directly discuss the impact of CSR on firm performance from the perspective of including disabled employees. The inclusion of disabled employees is a form of CSR. Internal employees, including the disabled, can make employees aware of the company’s efforts to fulfill social responsibility, which will result in lower turnover and improve the participation and potential of all employees [49]. For external stakeholders, the inclusion of disabled employees creates a positive corporate image [20,21]. Research by Henry et al. (2014) [18] confirms that companies that include employees with disabilities can gain a larger customer base and have the opportunity to win higher customer satisfaction and brand loyalty.