Technical Leaders are graded by multiplication, not addition

Today I learnt something incredibly useful while reading Becoming a Technical Leader, by Gerald Weinberg.

As Technical Leaders we are graded by multiplication rather than addition.Typically there are various dimensions to our grading, technical skills and the so called soft skills being two of them.

Let's imagine that one is very good technically but occasionally has a bad temper. In grading terms, we could say that technical skills are graded at 80 and soft skills at 40. Firstly, the grade of this person is not 80 + 40 but rather 80 x 40 giving a 0.32 instead of 1.2.This becomes more and more interesting as more and more skills are added to the equation.

A more interesting thing to note here, however, is that when grading by multiplication an increase in the skills with the lowest grade has a greater effect than when grading with addition.

With reference to the case above, let's imagine that one was to use addition for grading. It wouldn't make difference if a 10 percent increase happened in technical skills or soft skills, since 90 + 40 = 80 + 50.

However if we were to grade by multiplication, increasing by 10% the poorer skill would make a diffence, since 90 x 40 = 3600 whereas 80 x 50 = 4000.

Lesson learnt? As a technical leader we must strive to improve our poorest skills to increase our overall grades, because we are graded by multiplication rather than addition.