"The first data element I work to understand is the TAM or the total addressable market. This represents the total dollar amount that is currently spent on the type of product I am analyzing. I also work to understand projections for growth within the product sector. The future TAM can be even more important to understand when analyzing a product that will take time to develop and release.
I then work to estimate the portion of the total market share that the product I am working with will be able to represent. I typically offer a range that allows for unforeseen changes in the competitor market and shifts in my company's ability to quickly release value-add features.
The combination of these data elements helps me to understand the space a product currently occupies within the market, the potential for growth, and the level of effort required to capture a portion of the market from competitors."