Mother and Child Health: Research Methods G.J.Ebrahim Editor Journal of Tropical Pediatrics, Oxford University Press.
Types of Studies This set of slides provides a general introduction to different types of studies. In the sets that follow each type of study is further described together with its common variations.
The Fundamentals of a Study • Firmly established study objectives or hypotheses. • Carefully defined methods of assembling study subjects, avoiding bias in selection, and case definitions. • Making valid and reliable observations avoiding biased surveillance, variability among observers, and masking of observers. • Handling of incomplete observations, including what steps to take about subjects lost to follow-up, non-responders, or those whose status changes during the study. • Selecting appropriate comparison groups, identifying beforehand important factors that may influence the study hypotheses, and controlling for them.
Case Reports Outcome observed Agent acts Time Case Report
Case Series Agent acts Outcome observed Time Case Series
Cross-sectional Studies Agent acts Time Cases Normal Study Population
Case-control Studies Agent acts Time Yes Cases No Exposure History Yes Controls No
Cohort Studies Disease Present Exposed Time Absent Present Time Not exposed Absent
Clinical Trials Outcome New Treatment Improved Not improved Patients Comparison treatment Improved Not improved
Intuition and Logic in Research Dominant Mental Activity Intuition Feeling Judgement Experience Analysis Experiment Clinical trials Cohort Study Hi Case-control Study Cross-sectional Study Control over variance Case Report Case Series Qualitative Research Lo Potential for Misinterpretation Lo Hi