Occupational psychologist Memory Nguwi explains the flaws of using interviews to assess potential employees.
The most popular method used by organisations to select employees is the interview method. Despite its popularity, scientific evidence shows that the interview method is the most unreliable way to select employees. So why is it popular, why is it unreliable and what can be done about these shortcomings? Before answering these questions I want to point out that a study by McKinsey in 2007 shows that organisations that select employees on merit are achieving higher productivity compared to those that do not.
Research by Schmidt and Hunter has consistently shown that the interview method on average explains an average of 8 percent variation in employee performance. This means its predictive power is limited when it comes to predicting which employee will perform when put on the job. There a number of reasons why the interview shows such low level of predictive power. Most interviews are unstructured and unstandardised. This means that candidates who have applied for the same job are sometimes asked questions that have nothing to do with the job, making it difficult to assess their suitability for the position. Even in cases where they are asked questions related to the job, such questions are not consistently asked. Also, they are not asked in the same way to all candidates, making it difficult to assess and compare candidates vying for the same role. The other reason why interviews show low predictive power is that interviewers are poorly trained and rarely come for the interviews prepared.
Besides the above-mentioned shortcomings, the interview method suffers from a number of biases. The most common one is what is called confirmation bias. It says that we see what we want to see in interviewers. We use the interview to validate our own thinking about certain issues. This forces us to discount views that do not support our own thinking. This is why if you go for an interview and show any thinking that is not in line with generally agreed thinking in the organisation you will not get hired.
Have you also noticed that interviewers tend to like or favour candidates who have the same background, personality and interests as theirs? Again remember all this has nothing to do with the ability to do the job at hand. You may have also noticed that management plays a big part the interviewee. Candidates who are articulate and dress well are the ones that get hired even if they do not possess the capacity to do the job.
Most people think that because they are in senior roles, they know how to design interview questions and carry out interviews. As a psychologist myself, I know that interviewing skills do not come naturally to managers. Most organisations lose a glorious opportunity to get the right candidate because they unleash untrained interviewers to interview candidates for key roles in the organisation.
Research has shown that many organisations regret hiring decisions a few months after hiring individuals. In most cases, they only realise that the person hired is the wrong one when the person is already on the job and messing up when it is too late to do anything about it.
Before I go to explain how we can improve the hiring process by selecting the right selection tools, I would like to highlight other factors that are given higher priority but add very little value to the hiring process. You may have noticed that some employers put age preferences silently into the hiring process in order to get people of a certain age. Research has consistently shown that hiring people of a certain age range does not bring an extra value. Age explains 0 percent variation in performance for people occupying the same role except in jobs requiring physical ability. Unfortunately, employers waste time incorporating age when hiring.
More years of education for people in the same role adds very little change to the performance variation of these people. Extra years of education above what is required as a minimum for a job adds only 1 percent variation in performance. Also, note that extra years of experience over and above the minimum required for a role only adds 2.6 percent variation in performance for the people in the same role.
I am sure you can now see that some of the things organisations do when selecting employees bring very little value but cost a lot in terms of time and other resources. So how do you make the selection process more credible? Scientific research shows that after your initial selection of candidates based on minimum requirements: for example qualification (necessary for domain knowledge) and a certain number of years in a similar role or environment you must employ selection methods based on their predictive power.
Do not proceed to interview candidates before testing their cognitive ability. Cognitive ability and work sample tests have the highest predictive power of all selection methods. However, most organisations do it wrongly by interviewing first and then send people for psychometric tests. After psychometric tests, those who pass must then go through work sample tests as part of the assessment centre selection methods. They will go through role plays, presentations, in basket and group discussions to assess their suitability. It is very simple; if you want to hire an accountant, give them a real-life accounting task.
There is a lot that organisations can do to hire people on merit by following the best methods that have been scientifically validated in the selection of employees. The quality of people you hire will determine your organisation's success or failure. Remember, despite its popularity, the interview method is the worst method for selecting employees. However, if you are constrained by resources and you have to use the interview method alone, make sure you get expert advice on how this can be done to increase its predictive power.
Memory Nguwi is an Occupational Psychologist, Data Scientist, Speaker, & Managing Consultant- Industrial Psychology Consultants Ltd a management and human resources consulting firm.