This is from an article from Tomorrow’s Professor website.
USE PAST TENSE:
- To describe your methodology and report your results
- When referring to the work of previous researchers.
- To describe a fact, law or finding that is no longer considered valid and relevant.
USE PRESENT TENSE:
- To express findings that continue to be true.
- To refer to the article, thesis or dissertation itself.
- To discuss your findings and present your conclusions. Also use present tense to discuss your results and their implications.
(e.g.) Weight increased as the nutritional value of feed increased. These results suggest that feeds
higher in nutritional value contribute to greater weight gain in livestock. (Use past tense to indicate what you found [weight increased], but use present tense to suggest what the result