Jobseekers using their smartphones to look for work are likely to find frustration instead.

Recent studies have shown that many large employers have not adapted their job application Web sites for smartphones and tablets, a decision that analysts say could put them at a disadvantage for landing new staffers as an increasing volume of Web traffic comes from mobile devices.

The lack of a mobile-friendly job-application process may be especially limiting for low-wage workers, since this group is more likely than others to use their smartphones as their primary way to access the Internet.

Digital analytics firm ComScore reports that the number of people who have conducted job searches on smartphones has more than doubled in the last year, with more than 6 million people in the United States conducting such a search in February.

“For most candidates visiting most employers’ [mobile career] sites, it’s horrendous,” said Hope Gurion, CareerBuilder’s chief development officer.

The online job board examined the mobile career pages of 680 of its clients and found that 51 percent had mobile applications that were more than five Web pages long, making for a cumbersome experience on a small screen.

Another firm, iMomentous, evaluated the career sites of all the companies in the Fortune 500 and deemed 220 a “bad experience,” meaning their career sites were designed for desktops, not smartphones.

Other firms in iMomentous’s study had pages that were designed for use on mobile, but ultimately made the user go back to a desktop to submit an application.

Only seven companies earned iMomentous’s top rating.

Food services giant Sodexo is one company that has invested in a mobile hiring strategy and says it has seen favorable results from making the shift.

The Gaithersburg-based firm has not only optimized its careers page for mobile, it has also built a “Sodexo Jobs” app for iPhone, Android and Blackberry that allows prospective workers to search and apply for positions from a smartphone.

The company said the app has been downloaded 11,000 times since its debut in 2012. It has made 90 hires so far from candidates who came to Sodexo through the app.

Sodexo’s career Web page, which was re-designed for mobile three years ago, now receives 17 percent of its traffic from mobile devices.

“This is traffic that would’ve not been coming or been having a poor experience with us,” said Arie Ball, vice president for sourcing and talent acquisition.

There are several factors that analysts say contribute to the effectiveness and user-friendliness of a job application site.

“If you need to pinch and zoom and try to figure out where everything is, it’s just terrible,” said Eric Offner, vice president of sales at iMomentous, a company that has built a mobile platform for talent acquisition.

In addition to design-related issues, Gurion of CareerBuilder said the content of applications is often not conducive to mobile because it is too long and there are too many fields to fill out.

When using smartphones, “people usually have short windows of time and short periods of tolerance, and so you have to think about, ‘How do I adjust the types of information I want to capture with this person?’ ” Gurion said.

Some companies are already exploring ways to tighten up an application for mobile. For example, the employer could tap a phone’s geolocation capability to show only jobs that are near the applicant. Certain fields could be auto-filled based on other information stored on the phone. And more multiple choice questions could be asked in place of open-ended ones that require typing.

For employers that have not adopted a mobile-friendly recruitment strategy, analysts say a variety of factors could be holding them back. Many human resource professionals rely heavily on expensive applicant tracking systems that were not designed to work on mobile.

Another explanation for the lag, analysts say, could be that human resource professionals would have to shift dollars away from tried-and-true methods of recruiting to fund this newer tool.

“There’s really not a mobile budget today. It’s really not a line item that ever existed,” Offner said.