Statistical discrimination is a harsh mistress. If reliable measures of the quality of job applicants are unavailable for short-listing, such as credit checks, coarser, less reliable screening devices will be employed. That was the case when credit checks were prohibited in employment recruitment:
Looking at 74 million job listings between 2007 and 2013, Clifford and Shoag found that employers started to become pickier, especially in cities where there were a lot of workers with low credit scores. If a credit-check ban went into effect, job postings were more likely to ask for a bachelor’s degree, and to require additional years of experience.
There are other ways that employers could have also become more discerning, Shoag says. They might have started to rely on referrals or recommendations to make sure that applicants were high-quality. In the absence of credit information to establish trustworthiness, they may even have fallen back on racial stereotypes to screen candidates. The researchers couldn’t measure these tactics, but they’re possibilities.
Drug testing allows employers to dispel less accurate stereotypes about drug use among different ethnic and social groups. They increased hiring of minorities because a reliable measure became available of their drug use:
…after a pro-testing law is passed in a state, African-American employment increases in sectors that have high testing rates (mining, manufacturing, transportation, utilities, and government).
These increases are substantial: African-American employment in these industries increases by 7-30%. Because these industries tend to pay wage premia and to have larger firms offering better benefits, African-American wages and benefits coverage also increase. Real wages increase by 1.4-13% relative to whites. The largest shifts in employment and wages occur for low skilled African-American men.
I also find suggestive evidence that employers substitute white women for African-Americans in the absence of testing. Gains in hiring African-Americans in these sectors may have come at the expense of women, particularly in states with large African-American populations.
Employers test for drug use both for health and safety reasons and as a way of screening out less reliable employees. People who break the rules are not reliable employees and that includes taking drugs. In low skill jobs, what employers seek is a recruit who is friendly and reliable.
Testing of the skills of workers also showed similar results. What happened is that the ratio of black to white hirings do not change. The administration of these skills tests allowed the more productive of both white and black job applicants to be identified and hired.
Employers already had an accurate stereotype of the average skills of different ethnic groups. Administration of tests allow them to identify which members of each group were the most productive.
It is a standard result that statistical discrimination improves the chances of below-average applicants subject to the stereotype but harms those of above average quality. For that reason, applicants look for what methods of counter-signalling to show that they are indeed a quality applicant – make themselves stand out from the crowd.
Employers profit from developing screening devices that go beyond stereotypes to identify above-average applicants. They want screening devices that find those who do not otherwise stand out from the crowd because of difficulties in transferring credible information about their quality. This is a special difficulty with low-skilled vacancies because hiring is made based much more than on character than experience.