1 in 3 people have turned down a job offer because of a company's bad online reviews—but they're not always true

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Online reviews help consumers make decisions about everything including where to eat, what to buy and how much to pay for goods and services. They're also increasingly a place job seekers turn in order to evaluate whether they want to work for a potential employer.

In fact, one in three workers has turned down a job offer after reading negative reviews about a company online, according to a recent survey from Fractl. The digital growth agency polled 1,096 workers who left an online review of a former employer and, unfortunately for companies, disgruntled ex-employees are the ones most likely to post about their experience.

Over half of workers from the survey reported giving their former employer 1 or 2 stars.

Reviewers also stand by their words: Eight in 10 people reportedly have no regrets about the review they left. But 12% of people wish they were more negative.

Most ex-workers say their reviews were honest, but according to the survey, roughly 10% of workers admitted to lying or stretching the truth in their review. Almost half of dishonest reviewers say they did so in order to damage the reputation of their former employer.

Career sites only allow reviews from current or former employees. Glassdoor, the review site of choice according to the survey, enforces this by requiring users register with a permanent, active email address or social networking account. Once verified, users are limited to just one review per employer per year.

Scott Dobroski, a spokesperson for Glassdoor, tells CNBC Make It that each submission goes through a multi-tier review process to detect gaming or abuse, including screening through software programs as well as by humans, before it appears on the site. He adds that about 5% to 10% of content submitted to the site is rejected because it does not meet community standards.

Indeed, another review site mentioned in the survey, uses a combination of machine learning and human moderation to determine the validity of submissions, according to a company spokesperson. The company notes submissions can be rejected if they include discriminatory language, critical or spiteful comments on other reviews, allegations of illegal activity or defamatory content.

That being said, Dobroski says job seekers should still do their own research on a potential employer. They can also bring questions about negative reviews they've read to the interview itself.

Online reviews give just a narrow scope of what it's like to work with a given company, says Domenica D'Ottavio, lead researcher for the Fractl study. Part of the reason why: People may be more likely to focus on negative experiences than positive ones.

"I think job seekers should keep in mind that for every 1-star review, there are 10 5-star reviews that just haven't been written yet," D'Ottavio tells CNBC Make It. "It could be that lots of happy current employees have never left a review."

On Glassdoor, Dobroski notes the average company rating is a 3.5 on a 5-point scale, suggesting about 75% of current and former employee reviewers are generally satisfied with their experience with a company.

Whether employers respond to negative reviews online also sends a message.

"It's important to look at how the company is addressing its employee feedback on Glassdoor, if at all, and come prepared with questions to address these themes or concerns during the interview process and conversations with the company," Dobroski adds.

D'Ottavio says there could be another benefit of online reviews: Employers can use them as a jumping-off point to improve the experience for current workers. On many review sites, reviewers are prompted to list the pros and cons of working with the company, and some may be invited to offer advice to management.

According to the report, the areas ex-workers rated their former employers most negatively include bad management practices, a poor work environment, and high employee turnover. Companies may be especially incentivized to provide a better employee experience considering the tight labor market, where there are more open jobs than job seekers to fill them.

"I think that moving into 2020, there will be an increased focus on companies really homing in on their company culture —and I'm not just talking about free snacks and coffee," D'Ottavio says. Referring to survey findings of where companies were rated lowest, she adds: "Managers and people in positions of leadership should seek out best management practices by being an effective communicator and empowering their team to work autonomously and not micromanage."

D'Ottavio says the findings also indicate employers may want to consider revisiting their employee exit process.

"Conducting thoughtful exit interviews, and offering decent severance packages can leave a lasting impression and turn a 2-star review to a 4-star review," she says.

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