By definition productivity is measured by calculating the total output per unit of total input. What exactly you take as "input" and "output" entirely depends on your goals and what you think is important.
For example, many countries use Gross National Product or Gross Domestic Product as a productivity measure. However, there is one country (Bhutan) that thinks happiness is more important than money so they decided to measure Gross National Happiness instead.
Of course, you'll need to come up with a way to quantify your inputs and outputs. Here creativity also plays an important role.
For example, if your goal is to write good books then you need to quantify "good". One way to do this is to let a group of people read and rate your books, but you can think of many other ways; count the number of sold books, count the revenue of the sold books, see if your books make it on the best-seller lists, position on best-seller lists, number of positive versus negative reviews, etc.
My point is, the list of possible input/output used in productivity calculations is endless. If you think something is important and you can find a way to quantify it, then it can be used to measure productivity. This being said, you can say something about often used inputs and outputs. Many people have similar goals so often-used input/outputs are:
- Money
- Raw materials
- Energy
- Quality
(5. Reputation points on SE sites ;-)
One thing that is constant is time. Since a productivity measure is used to compare one situation with another (else why bother measuring it?), time has to be included somehow in the calculation. Without time there wouldn't be situations to compare.
