Let's define the scope: a survey on holiday planning habits cannot explain the motivation behind checking identity documents.
The survey collected data on holiday planning, not on the specific reasons why people check their documents so early.
For that, one would need to ask directly about motivations for verifying identity papers, not on general planning.
Without this information, we cannot decide that one directly informs the other.
For example, a traveler preparing their passport early may be due to an administrative processing delay and not their holiday planning style.