Developing an accurate Market Sizing estimation starts with clearly defining the market. Often, companies want to know the Total Available Market (TAM), Served Available Market (SAM), and Share of Market (SOM) for a set of products and services in a given region or geography. The Total Available Market (TAM) is the total revenue or sales within a particular market, Served Available Market (SAM) is the percentage of the TAM that a company can serve given its product portfolio and capabilities, and Share of Market (SOM) reflects the percentage of the SAM that a company currently or has the potential to serve. Scoping your market analysis from the get-go so that it is clear what you are trying to estimate is critical.

In Market Sizing, there are two basic approaches, either top-down or bottom-up. Top-down approaches are usually faster and cheaper, based on readily available data sources, are optimal for doing “quick and dirty” analyses, but yield less accurate estimations than a bottom-up approach. A bottom-up approach can often involve conducting qualitative research, as the data needed may not be publicly available. Identifying what the key variables are for generating an accurate market size calculation and using a combination of both approaches using multiple data sources can increase the reliability of your analyses.

Market size estimations should also include an analysis of the trends occurring in the specified market, which may require additional qualitative research. This is important not only for identifying risks and disruptive threats, but also to ensure that the market is moving in the desired direction and at the right pace that will increase the likelihood of profitability.

Generating a set of estimations using a range of data sources and comparing how similar they are will help determine their reliability. If the outcomes differ widely, additional research may be necessary to close the gap and arrive at a more consistent estimation of the market size.