Here the candidate should be able to succinctly summarize the findings made in the two previous steps and make a sound conclusion:
One possibility would be as follows:
The first-year sales for the new vaccine are very promising and expected to be around €1.778 billion.
To arrive at this number, we first estimated the theoretical potential market of the vaccine in 100 million children. However, due to the lower incidence for older children and to the high price of the vaccine, we figured out that only the parents of about 26.67 million children would buy the vaccine. Since only two of the three doses are administered in the first year, the expected sales would be of about €1.778 billion.
However, it is very important to mention that, since the vaccine prevents the disease for the entire life, only during the release children of different ages will be treated with it.
After the first couple of years, older children will have already been vaccinated. The consequence is then that only children at age 2 will be likely to be vaccinated in the future (if parents want to vaccinate their children, it’s logical that they do it the earliest possible).
This is an interesting example of substitute product produced by the client (in many cases the client has to react to a substitute that competitors bring to the market).
A good interviewee would achieve a good estimate of the potential market and then make the appropriate considerations to realistically estimate sales (defining what market share the new product will gain and under what conditions).