exercise for the reader
A subject, debate, or other matter that is not decided or dealt with directly by the author or presenter, but rather is left up to the judgment or interpretation of the observer, reader, or addressee. The report merely details the spending practices of the parties concerned; whether or not these payments were dubious in nature is left as an exercise for the reader. The politician's speech made broad references to invigorating the economy with practical, no-nonsense measures—what such measures might be, though, was left as an exercise for the reader.