Diseases, Conditions, Syndromes

Children of the '90s study completes COVID-19 antibody testing

Children of the 90s, a health study based at the University of Bristol, has today [10 November] published results from a study testing almost 5,000 participants for COVID-19 antibodies. The results found 4.3% reported a positive ...

Psychology & Psychiatry

Sharp decline in mental health for young Australians

COVID-19 is continuing to lead to worsening mental health outcomes for young Australians, with the highest levels of psychological distress for 18- to 24-year-olds observed this year, new analysis from The Australian National ...

Psychology & Psychiatry

Study highlights link between depressive symptoms and stroke risk

People with multiple depressive symptoms have an increased risk for stroke, according to findings recently published in Neurology: Clinical Practice. The collaborative study led by investigators at the University of Alabama ...

Medical research

Study upends understanding about joint injuries

An injury to the anterior cruciate ligament (ACL) can lead to severe osteoarthritis in both animal and human patients. Now, a new interdisciplinary study on the protein that lubricates our joints says that lubricant may actually ...

page 1 from 37

Longitudinal study

A longitudinal study is a correlational research study that involves repeated observations of the same items over long periods of time — often many decades. It is a type of observational study. Longitudinal studies are often used in psychology to study developmental trends across the life span, and in sociology to study life events throughout lifetimes or generations. The reason for this is that unlike cross-sectional studies, longitudinal studies track the same people, and therefore the differences observed in those people are less likely to be the result of cultural differences across generations. Because of this benefit, longitudinal studies make observing changes more accurate and they are applied in various other fields. In medicine, the design is used to uncover predictors of certain diseases. In advertising, the Communicus System, the design is used to identify the changes that advertising has produced in the attitudes and behaviors of those within the target audience who have seen the advertising campaign.

Because longitudinal studies are observational, in the sense that they observe the state of the world without manipulating it, it has been argued that they may have less power to detect causal relationships than do experiments. But because of the repeated observation at the individual level, they have more power than cross-sectional observational studies, by virtue of being able to exclude time-invariant unobserved individual differences, and by virtue of observing the temporal order of events.

Longitudinal studies allow social scientists to distinguish short from long-term phenomena, such as poverty. If the poverty rate is 10% at a point in time, this may mean that 10% of the population are always poor, or that the whole population experiences poverty for 10% of the time. It is not possible to conclude which of these possibilities is the case using one-off cross-sectional studies.

Types of longitudinal studies include cohort studies and panel studies. Cohort studies sample a cohort, defined as a group experiencing some event (typically birth) in a selected time period, and studying them at intervals through time. Panel studies sample a cross-section, and survey it at (usually regular) intervals.

A retrospective study is a longitudinal study that looks back in time. For instance a researcher may look up the medical records of previous years to look for a trend.

This text uses material from Wikipedia, licensed under CC BY-SA