What calculation is the most accurate way to estimate the size of a market?

The most accurate way to estimate the size of a market is to consider a comprehensive approach that factors in multiple important elements, which is why the option involving the calculation of [Population x % aware x % trial x % repeat] x per annum purchase is correct.

This method takes into account not just the total population but also their awareness of the product, the proportion of that population likely to try the product initially, and the likelihood that they will continue to purchase it regularly. The inclusion of "per annum purchase" helps quantify how often the average customer will buy the product in a year, providing a more precise estimate of the market potential.

By integrating these variables, this calculation effectively captures the various stages of consumer engagement: awareness, trial, and repeat purchasing. It reflects the reality of market dynamics better than simpler formulas that might only account for one or two factors, leading to a more reliable estimate of market size and growth potential.

The other formulations, while useful in isolating specific factors, fail to present the full picture necessary for a thorough market size estimation. For instance, calculations that only factor in awareness or a basic trial and repeat offer limited insight, as they overlook recurring purchase behavior and how it impacts overall market potential.