That’s according to a new paper from Harvard Business School and Accenture. The report, titled “Hidden Workers: Untapped Talent,” was written by Joseph B. Fuller, an HBS management professor and cochair of the school’s Managing the Future of Work project, alongside Manjari Raman, program director and senior researcher for the project, and Francis Hintermann, a global lead at Accenture Research.

“There is a vast reservoir of skilled hidden workers shut out of employment by inflexible rules established by companies,” the authors wrote. “The skills shortage can be addressed if companies relax their stringent definitions of the attributes they are seeking in applicants.” 

The skills gap has been a growing concern among everyone from former Secretary of State Condoleezza Rice and the governor of Pennsylvania to former IBM CEO Ginni Rometty and LinkedIn CEO Ryan Roslansky, who have all expounded on the material benefits of putting skills ahead of pedigree. Even Fuller himself agrees. “Do I think white-collar work will inevitably require a college degree? Absolutely not,” he told Fortune last month. “It will require certain types of technical or hard skills not necessarily indicated by college.”

His new paper takes that a step farther: The thrust is that for short-staffed or under-skilled companies, existing part-time workers who want to log more hours could be better utilized. In fact, many “qualified, eager workers” have caregiving responsibilities that keep them from jobs without sufficient flexibility. Few of those workers even make it to the application portal in the first place; some companies use hiring algorithms to filter out people with gaps in their résumés, a lack of degrees, or minimal experience. 

The authors drew their conclusions from Managing the Future of Work project surveys of nearly 9,000 “hidden workers” in Germany, the United Kingdom, and the United States, defined as those who are seeking a full-time job or who could work full-time but currently don’t. About 1,500 part-time hidden workers said they’d prefer to work more hours if their circumstances were different. 

Nearly a quarter said their résumé gaps prevented them from finding sustainable full-time work; nearly 30% blamed their minimal relevant experience. Just shy of one-third said they only work part-time owing to their caregiving obligations, which Fuller told Kara Baskin at HBS’s Working Knowledge publication are “the single-biggest driver” of hidden work. Indeed, most untapped workers (one-third) are caregivers, and 91% of those caring for children are women. 

This cohort may find it very difficult to earn more credentials or actively seek a full-time role because they can’t risk losing their part-time one, Fuller tells Fortune. “It’s a little bit like quicksand.”

Uncovering and uplifting hidden workers is good business

The term “flexibility” may bring to mind perks like remote work, asynchronous online hours, or four-day workweeks. Fuller has a different idea: Real flexibility stems from offering female and caregiving employees the space and accommodations they need to do both their office work and personal life work. Indeed, employers have created an “artificial shortage” of talent “by insisting that everyone fit a preset definition,” Fuller told Baskin at HBS. 

“Most career paths are still very much rooted in 1960s and 1970s logic,” he said. To move into the present day, most companies should give their job descriptions a fresh look, as well as reconsider the promotion process and assess travel and in-person work expectations. These are much more conducive to support and success than asking, “How do we provide ancillary services to enable the increasingly female workforce to work like their dads or their granddads did?”

Ultimately, the share of workers who will need—or simply prefer—this kind of flexibility will only grow, Fuller says. “There are so many more single-parent households,” he tells Fortune. “We don’t have an adequate eldercare infrastructure in the U.S., so more people will be living in multigenerational homes. That will be exacerbated by the increasingly undeniable housing crisis.” As such, the competitive relevance of being flexible will prove even more vital.

If companies find themselves with hard-to-fill positions, they should first look for areas of flexibility that they could offer to caregiving workers filling them, such as on-site day care, subsidized childcare, or—yes—flexible locations and hours.

Part-time workers with full-time ambitions need clear support, Fuller told Baskin, especially female caregivers since they’ll soon be a sizable portion of the future workforce. That starts with making issues that lead to hidden work “discussable,” he added. The pandemic certainly helped move that along; it’s never been more socially acceptable to share challenges and concerns with your boss—even ones that would originally seem too personal or unprofessional. 

Plus, when A.I. becomes commonplace and begins slashing jobs, “what will be left is the capacity to deal with other human beings,” Fuller told Baskin, adding that women are proven to have better social skills. Bosses will be hungry for good judgment, strong motivation, and the ability to collaborate and articulate a vision. “That sounds like the fun part of work to me,” Fuller told Fortune last month. “And much harder to automate.”