Delta Theory

Writing and delivering formal performance reviews can be very challenging. Evaluating discrete aspects of a person’s performance to come up with an overall “grade” can be controversial; ideally the ongoing communications between an employee and his/her manager is such that no big surprises arise during the review discussion. Occasionally this is unfortunately not true and I find a disconnect between my perception of a person’s overall performance and that of the person involved. To say the least, this is awkward. Sometimes it’s not possible to bridge the perception gap; other times I’ve found it very constructive to explain the “delta theory” and then interactively discuss with the employee being reviewed how it applies in his/her specific case.

What is the “delta theory?” Simply put it means that the performance rating of the individual is NOT just the sum of all the good that he/she has done. Rather it is the net contribution, determined by considering the delta between the employee’s positive accomplishments and any negative consequences of his/her behavior. Writing huge quantities of code is positive but if the software is exceptionally buggy that needs to be considered. Being productive on an individual basis is excellent but if that same person allows a negative attitude to actively distract others and affect their productivity then this consequence needs to be factored into the evaluation. Seems like obvious common sense to me.