Another point to consider is the planning fallacy : when you evaluate a shiny new project, you’ll under-evaluate the amount of work required to complete it. While for the already half-done project, you have a better view of what is left to do, of the unexpected problems to solve in it, … and you’ll have an evaluation of the work that is left which will be closer to the real amount of work (but usually still a bit off).
Basically to evaluate which of project A and B to do, you’ll do “expected gain of A”/”estimated work remaining on A” and compare it to “expected gain of B”/”estimated work remaining on B”. You address the issue of overestimating expected gain of new project compared to old project, but you should also consider the issue of underestimating the amount of work required for new projects.
So maybe using reference-class forecasting on the new project would help ? “Last time I had that new shiny project idea, I thought I would be done in 3 months, but after 6 months I only did half of it...”
Edit : sorry only saw afterwards that Viliam_Bur said more or less the same, but well, since I wrote my comment anyway, I’ll leave it ;)
Another point to consider is the planning fallacy : when you evaluate a shiny new project, you’ll under-evaluate the amount of work required to complete it. While for the already half-done project, you have a better view of what is left to do, of the unexpected problems to solve in it, … and you’ll have an evaluation of the work that is left which will be closer to the real amount of work (but usually still a bit off).
Basically to evaluate which of project A and B to do, you’ll do “expected gain of A”/”estimated work remaining on A” and compare it to “expected gain of B”/”estimated work remaining on B”. You address the issue of overestimating expected gain of new project compared to old project, but you should also consider the issue of underestimating the amount of work required for new projects.
So maybe using reference-class forecasting on the new project would help ? “Last time I had that new shiny project idea, I thought I would be done in 3 months, but after 6 months I only did half of it...”
Edit : sorry only saw afterwards that Viliam_Bur said more or less the same, but well, since I wrote my comment anyway, I’ll leave it ;)