Data might be Primary or Secondary. Fortunately the second of these is a potential solution to the problem of low resources. To understand the values and preferences of passengers, there are a range of sources of secondary data already available.

The National Rail Passenger Survey provides information on the population. Sources such as this are useful in this context because they provide a rounded view of all rail users in the country. There are also continental datasets which provide a comparison when assessing passenger satisfaction. Secondary data can also be used in conjunction with primary data, explained below.