Job prospects get tripped up by everything from brief résumé gaps to ballooning job descriptions from employers that lessen the chance they will measure up. Lead Harvard researcher Joseph Fuller cited examples of hospitals scanning résumés of registered nurses for “computer programming” when what they need is someone who can enter patient data into a computer. Power companies, he said, scan for a customer-service background when hiring people to repair electric transmission lines. Some retail clerks won’t make it past a hiring system if they don’t have “floor-buffing” experience, Mr. Fuller said. This reliance on automation filters big sections of the population out of the workforce and companies lose access to candidates they want to hire, he added.

Harvard’s findings—resulting from a survey of companies and workers conducted by the business school’s Project on Managing the Future of Work and consulting firm Accenture PLC—offer new insight into the current challenges of matching employers with potential employees as the economy reopens following a pandemic-led downturn. That process is proving to be unusually slow and complicated. The number of open U.S. positions surged to a record 10 million in June, the most recent month for which government data is available.