I second this question. There are good nonprofits which will find it difficult to answer precisely, e.g. one which focuses on basic science research (which has

I second this question. There are good nonprofits which will find it difficult to answer precisely, e.g. one which focuses on basic science research (which has, over the course of human history, contributed rather a lot to human welfare). But it is certainly a question that nonprofit founders should be thinking about right from the start, and producing vague estimates accordingly, just to get into a quantitative frame of mind; otherwise it is a very bad sign.