Is It Possible To Make Employee Reviews Objective?
The short answer to the question is NO. The longer answer is that it is possible to make employee reviews more objective. Here's why.
Whenever human beings are asked to make judgements, they do so with a degree of subjectivity. Even in cases where the thing being judged can be measured, there's still room for subjectivity. There will always be some degree of subjectivity with employee reviews, because they involve human judgement.
In cases where an employee is being evaluated according to criteria that can be measured accurately, it is possible to make things more objective. For example, it's possible to evaluate a sales person by looking at their total sales figures, and those numbers are measurable in an relatively objective way. But there's a catch. It's easy to measure trivial things objectively, but it's really hard to measure things that are important to a business in an objective way.
In the sales example, it may be that a salesperson's personal sales are high (as objectively measured), but that person achieved those sales figures by poaching on the territories of his or her colleagues. So, that person's success is a result of damaging the success of others? How do you measure the overall value of that employee? It's virtually impossible to measure the effects of a person on the people around them. It could be that a salesperson with a lower personal sales total is actually more valuable than someone with a higher sales total, if that high sales person harms others in the organization.
There's another catch. As you try to measure performance in both a meaningful and objective way, the costs of trying to do so increase exponentially. You'd get so caught up in collecting objective data by which to measure employee performance that nobody would get any real work done.
Striving for total objectivity is a mistake. If we treat employee reviews as opportunities to discuss performance -- communicate and improve it, and put manager and employee on the same team, we don't need reviews to be totally objective. Yes, objectivity is a good thing. But it's not completely possible, and it's costly.