Tech-based education and training firms are selling at premium prices, and are fetching more than the health and medical companies that used to get the best prices, a review of thousands of U.S. small-company sales shows.

Among firms with $10 million to $500 million in yearly revenues, 165 education and training firms that were sold last year changed hands for an average of nearly 13 times earnings, before interest, taxes, and amortization and depreciation. That's up from seven times earnings in 2012, according to Capstone Partners LLC of Boston, which advises companies for sale and collects business-sale data.

Health and medical small-business prices, by contrast, have been nearly flat in recent years. Almost 1,600 medical- and health-related firms tracked by Capstone sold for an average of about 9.4 times earnings last year. That's little changed from prices in 2012, while for other service-sector companies, sales premiums have risen.

Why are investors paying extra for education firms? With U.S. unemployment below 5 percent and companies complaining they can't find computer-literate workers, "businesses are now looking for training solutions to strengthen, retain, and provide growth opportunities for their workforce," Jacob Voorhees, a Capstone managing director, told Capstone clients in a recent report.

Corporate hiring departments, which have cut back direct worker-training programs, have been hiring tech-savvy training firms to sort applicants and prep new staff. The training firms' growth has lately attracted wealthy buyout funds. In one of the larger deals, a group headed by Blackstone Partners LLC in April paid $2 billion in equity and debt for Massachusetts-based Ascend Learning, which focuses on medical-industry education and test prep.

Voorhees listed 25 recent "e-learning, corporate, and professional training" mergers and acquisitions, with targets in 13 states and two Canadian provinces. Buyers ranged from large private-equity funds, to other private education companies, to a radio station. Malvern-based American Institute for Chartered Property Casualty Underwriters purchased Wyoming-based Polestar Performance Programs Inc. for an undisclosed sum, to provide sales training. The only Pennsylvania firm on the list, the biotech/pharma/medical-device training company Learnaboutgmp, based in Schnecksville, Lehigh County, was purchased by Azzur Group LLC.

Investors have come to believe that digitally enabled for-profit education providers are to competing public education systems what ride-hailing giant Uber is to old-fashioned cab companies — a much more connected, better-targeted, and efficient service, said Andrew T. Greenberg, a Philadelphia investment banker  at Fairmount Partners and chief executive of GF Data Resources, which supplies deal data to Capstone and other deal advisers.

That doesn't mean all start-ups in the sector are a good bet, Greenberg added. Like Uber, private-education companies have attracted investors, both "for the superior execution on market opportunities and the hubristic overreaches," he told me. There have been "lots of hits in for-profit training, but lots of misses as well. The lofty valuations reflect the hits."

In the early 2010s, after the Obama administration's expansion of Medicaid, health and medical firms attracted higher bids relative to most other service sectors. But since then, with cost concerns pressuring medical companies, other sectors — business services, consumer products, and government and defense companies, which formerly trailed medical and health services — have been sold at increasing prices and now command price-to-earnings premiums similar to health and medical deals.

Companies in all those service sectors tended to sell at higher prices than small manufacturing firms, which sold last year for about 7.9 times earnings. Family-owned factories, with higher facilities and materials costs, have consistently attracted lower offers than service firms in Capstone's database.

Only software tech and telecom companies tend to sell at higher premiums than education and training firms compared with profits. Indeed, since small tech firms often spend heavily on engineering and marketing so they can grow quickly and attract investors, they frequently aren't profitable. So small-tech firm valuations are typically measured against company sales, rather than profits. Tech companies have sold at roughly three times sales over the last five years, Capstone found.

Small-company sales in general hit a lull immediately after last fall's presidential election. That included a slowdown in education firm sales volume, if not in prices, Capstone's Voorhees noted.