What is the effect of ageism on people over 50 years old in the workplace?

Here is the result of twenty-three studies by Krings, Sczesny, and Kluge (2011) and Shiu and colleagues (2015), identifying negative stereotypes and perceptions of older workers:
• Regarding performance and productivity, respondents viewed older workers as less skilled and their performance unsatisfactory.
• Loretto and White (2006) also found that more than 50% of employers believed that performance declined after 50.
• In the study by Van Dalen and colleagues (2009) reviewing cultural diversity in stereotypes sustained by employers in four European countries, it was seen that employers in the Netherlands held more negative perceptions of seniors productivity than in Great Britain, Spain, or Greece. Additionally, results show that Dutch employers did not view older workers as valuable assets in resolving future labour market shortages.
• Unemployed older workers interviewed by Berger (2009) noted that employers regard older workers as poor investments.
• Truxillo and colleagues (2012) reported that the age of students did not reduce the negative perceptions of older workers.
• Van Dalen and colleagues (2010) also found that the younger the respondent, the more negative, the older workers’ productivity perception. Employers younger than 35 years seem to have the worst opinion of older workers’ productivity.
Assumptions related to decreased performance were associated with a variety of negative stereotypes. For example, limited ability to use new technology was a belief classified in eight articles. Employers’ perception of limited physical and mental ability to perform at work was also classified studies. In terms of perceptions of older workers’ capacity and eagerness to engage in training and promotion, the views expressed by a manager interviewed by Fuertes and colleagues (2013) that “the older the workers are, the less interested they are to do training.”
• Kluge and Krings (2008) also found that 53% of workers of all ages believed older workers are harder to train, and 52% believed older workers are less enthusiastic about challenging jobs.
• Maurer and colleagues (2008), employing a cross-sectional survey design, observed that the internalization of the idea that older workers lack the capacity and desire to learn was related, in part, to ageist stereotypes upheld by coworkers and society.
• In a research conducted in Korea, internalization of the assumption that older workers are of less importance and therefore deserve less pay was demonstrated through a quote from a 67-year-old participant who discussed his feelings toward being given extended working hours with a reduced salary once reaching retirement age. Negative biases toward older workers concerning adaptability, flexibility, and enthusiasm to change were also seen to be held by employers.
• Malinen and Johnston (2013) used a self-report survey to measure explicit and implicit attitudes of university students toward older and younger workers. Results showed that while the precise measure did not explain a negative bias against older workers, the implicit measure did, however, show the embedded nature of ageist attitudes toward older workers.