1. Knowledge of the researcher. It’s important to consider the researcher’s capacity and capability in the field which he/she wants to discover. In sense, it is in his proximity of study in order for him/her to do such approach
2. Tool used. Making sure whatever measurement the investigator is using should be valid and reliable. Avoiding the possible results to become biased and unstable due to errors which should be avoided.
3. Sampling method. Obtain the samples which are appropriate and that would cover the entire participants studied –not a half but the entirety of what you want to study. Entirety means as much as the possible sample covers.
4. Population. Knowing the involved participants and respondents in the study, properly defining and clustering helps the study avoid bias.
