In the following sentence:
I assumed the usage of 所 in this case is, according to Pleco:
[as a noun without 的, esp. when the verb is monosyllabic]
But in this sentence there is no preposition such as 据. The whole sentence would work fine even without 所 I think.
So what does the 所 work for and what meaning does it have, compared to the case where 所 is not used?