Managing projects by comparing the planned task duration with execution is a widespread practice. In most cases, it is also one of the parameters in the appraisal of resources working in projects. Despite the widespread use, managers are also aware that the uncertain reality of project environments can cause actual durations to be different. The difference has potential for erroneous decisions and consequent disharmony in work place.
According to Error Management Theory, when making decisions under conditions of uncertainty, two kinds of errors can occur – “false positives”, i.e. deciding that a risk or benefit exists when it does not, and “false negatives”, i.e. failing to notice a risk or benefit that exists. If managers use the planned durations as way to evaluate resource performance, there is a chance of managers being unfair because of a “false negative” measurement bias: declaring an efficient person as inefficient. The fact that a person was late as per planned duration does not necessarily mean that he was inefficient. Maybe he gave his super best despite the uncontrollable uncertainties and his special efforts prevented potential additional delays. One cannot deny the presence of “false negative” measurement bias but there could be an argument on the extent of bias (or its statistical significance). Well there is no study in public domain evaluating the statistical significance but we can refer to our collective experience. It is not uncommon for most resources with lower grades blaming systemic reasons for their low performance. We cannot just ignore them as “excuses”. The unfairness of most appraisal systems in the project environment is perhaps one of the “open” secrets of the project environment. We call it a secret, because whenever you confront managers with the problem, many claim that, with adequate experience, they can arrive at a “right” or the “correct” reference single point task duration. Statistically speaking, the words “right” or “correct’ estimate sound like oxymoron. With few clarity questions, one can understand that word “accurate” is usually interchangeably used for the word “realistic”. So what is realistic estimate? It is a duration considered achievable in a typical environment of uncertainties. This implies that the estimate is adequately protected (or buffered). If most task durations are buffered to protect from uncertainties, then a resource completing a work on planned time does not necessarily mean that he is efficient. So there could be the second error in decision making: the “false positive” measurement bias or declaring the inefficient person as efficient.