In the social media age, when a company's employment brand is more important than ever, it's a great idea for companies to always keep the issue of candidate perception in mind when implementing pre-employment testing. Given that the trend is increasingly towards testing early in the hiring process as we discussed here and here it's important to consider the question of how much testing is appropriate when the tests are one of the first points of contact a candidate may have with your organization.
We analyzed a lot of data (about half a million tests) to help answer this question. As the graph below makes clear, candidates complete the tests much less frequently when the length of the test exceeds 40 minutes.
The completion rates for batteries less than 40 minutes in length always exceed 75%. If this seems low, consider that many candidates encounter the test through a link in a job posting, and may simply close the test window after deciding they don't have the time, ability, or inclination to take the tests. If candidates won't spend 20-30 minutes applying for a job, chances are they weren’t serious about working for your organization in the first place—we call this group "resume spammers." Interestingly, this 75%+ completion rate is no different for a very short (less than ten minute) test than it is for a 30-40 minute test.
However, in cases where candidates are asked to take a test battery that is longer than 40 minutes, the completion rates are significantly lower: 66% for 41-60 minute tests, and 60% for tests lasting longer than an hour. It seems that the point at which "test fatigue" begins to discourage candidates can be pinpointed: it’s after 40 minutes. This is why we recommend that our customers keep test batteries under 40 minutes in length whenever possible. This is especially true for remote testing done early in the hiring process. It is impossible to know from the data, although it seems highly likely, that candidates will have higher completion rates for tests given on site, for several reasons—the main one being that if candidates perceive themselves to be under serious consideration for a job, they are much happier to spend a long time being assessed.