Every so often, some poor high-flying executive finds himself publicly humiliated when it emerges he hasn’t been entirely honest about his qualifications. The latest such episode saw Walmart communications boss David Tovar resign from the retailer after it emerged the art degree the vice president said he had received from the University of Delaware had never been awarded. Cue embarrassing headlines all around the world.

But just how common are these fibs? Are the high-profile examples of CV creativity isolated incidents or are candidates for jobs, at whatever level of the company, routinely making it up as they go along?

First Advantage, a business which offers pre-employment screening services, reckons far more candidates are dishonest than employers realize. More than one in four of the thousands of CVs it screens include inaccuracies, the company says. And while not all of the untruths are desperately serious, or even necessarily deliberate, a third are considered ‘major’ – that is they are of significant concern to the employer.

Traci Canning, managing director of First Advantage in Europe and the Middle East, says lying job applicants are making a big mistake. “Honesty really is the best policy,” she says. “Candidates would be better served by accurately stating their skills and experience because any accuracies will be uncovered during the screening process.”

That’s true, of course, for those that go through such a process. But not all employers use screening companies – smaller businesses, in particular, may not have the resources to use such a service during the recruitment process.

In which case, you need to be on the look-out for dishonest employees yourself. Start with the four big lies First Advantage reckons are most common.

“I got these grades.”

No, you didn’t. More than a third of the education checks made by First Advantage uncovered discrepancies and inaccuracies – typically relating to when, what and where the candidate studied. That might be anything from claiming to have a higher exam grade than was actually achieved to entirely made up degree qualifications.

“I’m professionally qualified.”

No, you aren’t. Almost a quarter of the professional checks made by First Advantage found incorrect information had been supplied. Candidates fibbed about their professional qualifications, the licenses they held and their membership of various professional organizations.

“I used to do this.”

Apparently not. A quarter of all the checks First Advantage made on candidates’ employment records turned up inaccuracies. People don’t tell the truth about where they’ve worked in the past and they’re often tempted to exaggerate the seniority of the roles they held.

“I’ve always worked”.

Really? One common ploy is to use false dates in order to gloss over periods when the candidate wasn’t working. That might be to hide a period of unemployment about which the candidate feels uncomfortable, or something more serious – even a spell in jail.

How do employers without access to screening services spot these lies? There’s no substitute for careful background checks. Most academic institutions have publicly-available records that enable employers to check claims made about qualifications and exam results. The same is true of professional organizations. Work references need to be cross-checked carefully too.