retrospective study vs prospective study

#RETROSPECTIVE STUDY VS PROSPECTIVE STUDY FREE#

Information or data is collected from past clinical records and the outcome of interest is investigated.Cohorts are defined from a previous point in time, and are not followed up in the future.Example: In a prospective cohort study researchers compared four different groups of women (two at-risk groups, two low-risk groups) to investigate which groups were more likely to develop PTSD symptoms after a birthing event.The two groups of cohorts (exposed and un-exposed) are followed prospectively over time to track the development of new disease.There are two types of cohort studies: Prospective and Retrospective.

#RETROSPECTIVE STUDY VS PROSPECTIVE STUDY FREE#

The participants are divided into two groups – the first group is the ‘exposure’ group, the second group is free of the exposure.

The participants must be identical, having common characteristics except for their exposure status.

A cohort study starts with the selection of a group of participants (known as a ‘cohort’) sourced from the same population, who must be free of the outcome under investigation but have the potential to develop that outcome.

Cohort Studies are a type of observational study. In Introduction to Study Designs, we learnt that there are many different study design types and that these are divided into two categories: Experimental and Observational. The study is now in its fifth decade and has produced over 1200 publications and reports, many of which have helped inform policy makers in New Zealand and overseas. This study is known as The Dunedin Study and it has followed the lives of 1037 babies born between 1 April 1972 and 31 March 1973 since their birth. These findings (and more) have come out of a large cohort study started in 1972 by researchers at the University of Otago in New Zealand. What type of study is a prospective cohort study?Ī research study that follows over time groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) and compares them for a particular outcome (such as lung cancer).Did you know that the majority of people will develop a diagnosable mental illness whilst only a minority will experience enduring mental health? Or that groups of people at risk of having high blood pressure and other related health issues by the age of 38 can be identified in childhood? Or that a poor credit rating can be indicative of a person’s health status? This result is possible because there are definitive behaviors or characteristics available for researchers to observe. A prospective cohort study can more clearly indicate the temporal sequence between an exposure and an outcome. What are the advantages of a prospective cohort study?Ī prospective cohort study provides clarity of the temporal sequence. On the other hand, a major disadvantage of cohort studies is that it is not possible to establish causal effects. What is a disadvantage of a cohort study compared to a clinical trial?įinally, because a cohort study has usually broader inclusion criteria and less exclusion criteria compared to an RCT, its results may be more generalizable to clinical practice. Thus, this study design is inefficient for investigating diseases with long latency periods and is vulnerable to a high loss to follow-up rate. The disadvantage of a prospective cohort study may be the long follow-up period while waiting for events or diseases to occur. What is a major limitation of the prospective cohort study? Since they depend on review of charts that were originally not designed to collect data for research, some information is bound to be missing. … Retrospective studies however have several limitations owing to their design. Retrospective studies are an important tool to study rare diseases, manifestations and outcomes.

Why is retrospective design a limitation? prone to recall bias or misclassification bias.

controls are often recruited by convenience sampling, and are thus not representative of the general population and prone to selection bias.inferior level of evidence compared with prospective studies.What are the limitations of a retrospective study?

Retrospective study vs prospective study