Esperanto in Scotland, Chapter 2, Exercise 2
Sample answer.

Why unreliable: reports were often written by club members or friendly journalists to
encourage readers to join, so "flourishing" is an opinion, may reflect one good evening,
and gives no number. Two reports of the same club can differ (in 1908 The British
Esperantist called the Dundee club "still small").

Better evidence: (1) membership lists or subscription records; (2) attendance counts
for individual meetings; (3) photographs with people counted; (4) reports from more
than one independent source.