😦 A study conducted in 1965 identified that argument mapping leads to clearer writing.
Some reporting verbs require a ‘that’ clause, others do not:
🙂 A study conducted in 1965 showed that argument mapping leads to clearer writing.
🙂 A study conducted in 1965 identified improvements to writing following argument mapping.
Reporting verbs not followed by that are usually followed by a noun phrase. Unfortunately there is no strategy to determine which verbs require that and which do not. You just have to memorise them. The best way to acquire useful reporting verbs is by reading journal articles and academic text books. To get you started, here is a list of common reporting verbs followed by that:
😦 Chomsky (2014) argued that grammar monopoly is an effective way to highlight first language interference.
I know, I know. 2014 is past and finished, so you want to use past simple tense. However, in this case the currency of the idea – is it recent and/or valid? – is more important than when it was written.
The currency of an idea can occasionally be difficult to determine, but in most cases it is obvious. If we assume that Chomsky is still alive (as he is at the time of this writing) and that his idea is still current then we use present simple tense, even if the idea was written in the finished past:
Chomsky (2014) argues that Grammar Monopoly is an effective way to highlight first language interference.
In most postgraduate writing we are dealing with current ideas, from recent sources, and so most of the time you will need present tense for your reporting verbs.