How accurate is recommendation data from Glassdoor?

Glassdoor is an online forum where people are invited to rate their current or former companies. Glassdoor provides a valuable service because it allows people to anonymously provide feedback to other job seekers, as well as the company itself.

However, in many cases there is almost no relationship between Glassdoor ratings and more comprehensive internal surveys. Glassdoor has great uptake in the New Tech space (see below). As we have comprehensive New Tech data, we thought it might be interesting to draw our own comparison.

We recently published a report based on our work with many of the world's fastest growing New Tech companies. For many of those companies we have data on how likely employees say they are to recommend the company as a great place to work (similar to the Glassdoor measure) asking if employees would recommend their company to friends or family.

This "recommendation question" is often used as a basis for deriving what is often called a Employee Net Promoter Score (eNPS) . We decided to take a look at some of the companies where we have good comparable data to the Glassdoor data.

We identified 13 New Tech companies for which we had strong, recent data (> 80% of employees) for the recommendation question. These companies also had at least five Glassdoor reviews. The chart below shows the difference between Culture Amp and Glassdoor measures.

Glassdoor versus Culture Amp ratings: Percentage of employees who would recommend 13 New Tech companies as a place to work. Glassdoor versus Culture Amp ratings: Percentage of employees who would recommend 13 New Tech companies as a place to work.

Quite clearly the Glassdoor scores are generally lower and in some cases more than 20% out relative to the more representative data from Culture Amp.

Glassdoor reviews tend to paint a more negative view of companies recommendation scores. Given the variability it is unlikely that anyone could rank companies using Glassdoor. We did notice a slight trend towards better comparisons when there were more reviews. However, the effect was not terribly strong.

These results match the larger sample comparisons provided by other research mentioned above. These suggest that Glassdoor reviews may only provide a very selective and narrow view of what companies are truly like to work for. It might be useful for Glassdoor to publish internal data where it can also be verified and deemed comparable as this would enable prospective employees to make a more informed decision.

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