Writing Research Paper

http://anthropology.ua.edu/bindon/ant570/pap_rule.htm

In a research report (dissertation/thesis/article) when you are talking about what you did you use the past tense. In fact, most of the paper should be in the past tense.  “In this study, Thai people’s eating habits were (or “have been”) investigated.  It was found that Thai people like to eat.”  Notice “investigation” is in the past since it is over at the point where you are writing the dissertation, but “like to eat” is kept in the present because it expresses a reality that is still true in your opinion.  Here it would sound strange to me to say, “It was found that Thai people liked to eat,” even though some authors would insist in both verbs being in the past in order to retain order through parallelism.

As a writer, you have to decide what you want to communicate, and then choose the verb/tense form that makes the most sense in the context.  It is a good idea to use language that is as standard as possible so you do not draw the reader’s attention away from the ideas you are trying to communicate and toward the language itself. However, if you try to follow the “rules” of form too strictly, that too can create situations where you find yourself saying things that border on the absurd, like “Thai people liked to eat.”
The main point is choose the tense, and other matters, according to how you want the reader to perceive the “event.”

http://eflwriting4life.wordpress.com/2011/03/06/tense-use-for-research-papers/

Present tense is used for relating what other authors say and for discussing the literature, theoretical concepts, methods, etc. In addition, use the present tense when you present your observations on the literature.

Past tense is used for recounting events, results found, etc.

Verb tense consistency

1.  Use present tense when writing essays about

• your own ideas 
• factual topics
• the action in a specific movie, play, or book

2. Use past tense when writing about

• past events
• completed studies or findings,  arguments presented in scientific literature

3. Use future tense when writing about

• an event that will occur in the future.