Chapter-03 Planning and Design of a Study

BOOK TITLE: ABC of Research Methodology and Applied Biostatistics—A Primer for Clinicians and Researchers

1. Parikh Mahendra N
2. Gogtay Nithya
Publishing Year
Author Affiliations
1. Seth GS Medical College and Nowrosjee Wadia Maternity Hospital, Mumbai, Maharashtra, India, Seth GS Medical College and Nowrosjee Wadia Maternity Hospital, Mumbai, Seth Gordhandas Sunderdas Medical College, Nowrosjee Wadia Maternity Hospital, Mumbai, Maharashtra, India; Shushrusha Citizens’ Cooperative Hospital, Mumbai, Maharashtra, India; Fertility Sterility, India; The Journal of Obstetrics and Gynaecology of India, Nowrosjee Wadia Maternity Hospital, Mumbai, Mumbai, Maharashtra, India, Mumbai
2. Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Mumbai, Maharashtra, India; Journal of Postgraduate Medicine, Seth GS Medical College and KEM Hospital, Mumbai, India, Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, Mumbai, India
Chapter keywords


Hypothesis is a hunch, conjecture or supposition which the investigator uses to explain his results. Null hypothesis and alternate hypothesis form the basis for comparing groups. Inclusion and exclusion criteria must be defined before enrollment. Recruitment is time consuming. Statistical errors are of two types, alpha and beta and are usually set at 5% and 10% respectively. The power of a study is inversely related to the beta error. A study should have internal as well as external validity. Internal validity is affected by various biases that creep in during the study. Random error occurs by chance. Systemic error must be anticipated in the beginning and minimized to the possible extent. Confounder is associated with the exposure and affects the outcome and its measurement. There are many types of end points primary ones being most important. End points should be few that are easy to achieve during the study. Follow up of the participants over a defined period of time is an important part of any study. Data is generated/collected by the researcher in many ways. It must be accurate and honestly recorded. It is tabulated and must be analyzed and evaluated statistically. Every research needs money. There are many organizations which are willing to support good research even by students.

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