Competition

A

Great idea. Few best sellers explicitly cover this theme.

Profitability

C

We start hitting the $1000/month mark and more in sales - provided you rank in at least one best seller list. You can afford investing hundreds of dollars in marketing and promotional tools knowing that you have a greater chance of recouping your investment.

Difficulty

A

You can easily make it to most best seller lists with less than 3 sales a day on average. This topic is ideal for new writers. Provided that the profitability and competition scores check out, you found your gem!

Niche

E

A very narrow niche that may hurt your profitability. If you publish multiple books on the subject they will most likely compete with each other in a small pool of categories

C

After all, you've got to have passion and dedication about this idea to make it work.