Research design

Content:
This Mednesday, Dr. Petitti introduced us classification of research design in epidemiology research. There are three types of epidemiology research--descriptive studies, observational studies and experimental studies. Descriptive studies aim at description, the goal of experimental studies is causual inference, while observational study can study causual relationship or not.

Observation studies can be devided in to cross-sectional studies, cohort studies and case-control studies. The difference between cross-sectional studies and cohort studies is that the former one measures prevalence while the latter one measures incidence. In my opinion, cross-sectional studies are more close to descriptive studies. Usually, cross-sectional studies just state a situation rather than analysis the reason of the situation. The difference between cohort studies and case-control studies is that cohort studies need researchers to on-going monitor the subject which expose to risk factor to ascertain the outcomes, while conducting case-control studies, researchers do not need to wait, what they need to do is to compare cases with controls to find out the causaul relationship between risk factor and outcome.

Experimental studies are very similar to cohort studies, the only difference is that in a experimental study, researchers manipulate variables, while in cohort studies, researchers just wait. Experimental studies can be devided into Post only design and Pre and Post design. The difference between them is that the latter add information of baseline to assure adequacy of randomization and comparability at baseline.

I like the way Dr. Petitti giving her lecture that she compared different types of studies to help us understand the trait of each research design.

Posted by
Jing Lu