Retail jobs are changing, and the arrival of robot “workers” in stores will only accelerate that evolutionary shift.

Walmart recently acknowledged that it is testing the use of robots that can move down the aisles of its stores, scanning shelves for out-of-stock items, missing shelf tags or other problems. The robots are said to be 50% more productive than human workers at the task, and they are able to scan shelves three times faster with considerably more accuracy. They can also do the job more often than their human counterparts.

Other retailers — including Target Corp., Schnuck Markets and, more recently, Ahold USA — are testing similar systems.

That may seem like bad news for a retailer’s human workers. A recent paper, “Robots and Jobs: Evidence from U.S. Labor Markets,” by the economists Daron Acemoglu of M.I.T. and Pascual Restrepo of Boston University found that the deployment of robots hurt both employment and wages. The researchers did find that in some cases the productivity gains that result from automated technology can lead to employment gains even within the same industry.

How this will play out in the retail industry is a big deal. According to the National Retail Federation (NRF), the retail industry is the nation’s largest private-sector employer, supporting one in four U.S. jobs — or about 42 million working Americans.

Walmart says that its aim is not to use the shelf-scanning robots to replace human workers, but instead to free them to focus on serving customers and selling merchandise, jobs that most store associates would prefer to checking shelves anyway.

A similar dynamic has played out with the rollout of prescription-filling robots in the pharmacy. Advocates point out that the technology can handle the routine but important tasks of identifying and counting pills, while freeing pharmacists to spend more time counseling patients.

In a recent blog post, NRF director of research Allison Zeller pointed out that the skills needed by workers in retail stores have already been shifting toward those that are more ­customer-focused.

An analysis of retail sales associate job postings from 2007, compared with comparable job postings from the 12 months prior to October 2017, identified some important trends.

“According to the data, skills in customer service and marketing are more in demand today than in 2007,” Zeller wrote. “Retailers from all sectors are reworking and redefining their store strategies, with retail sales associates front and center.”

Zeller cited the consumer electronics chain Best Buy as an example of the trend. The company positions its employees as “knowledgeable technology advisors,” she wrote, and considers them a key factor in its recent success.

“Retail sales associates reflect the brand, and retailers are looking for employees who build customer relationships and can market their products most effectively,” Zeller pointed out.

“The role is less about folding sweaters [than] it is about selling them, and retailers are looking more and more for people to come into the role with the skills to sell. As retailers seek to fill retail sales associate positions that execute strategy, basic, foundational job skills are often a position requirement.”

Zeller concludes by pointing out that retailers are responding to the need for more skilled employees by investing in training. The NRF Foundation’s RISE Up program, launched this year, is designed to provide entry-level workers with the skills and education needed to get a job in retail and advance their careers. And Walmart’s investments in technology haven’t stopped the company from opening Walmart Academy training facilities across the country. The company said earlier this year that it planned to have 200 open by the end of this year, each providing two-week to six-week programs in advanced retail skills.