Longitudinal studies

• Longitudinal research is the collection of data over time.
• The main advantage of longitudinal research is that it allows researchers to observe changes or trends over time, which can be useful when studying complex phenomena such as developmental processes.
• A disadvantage of longitudinal research is that it requires significant resources, including funding, staffing, and participant recruitment efforts.
• A disadvantage of longitudinal research is that it requires significant resources, including funding, personnel, and equipment, making it more expensive than cross-sectional research.
• Another limitation of longitudinal research is that participants may drop out due to various reasons, leading to sample attrition and potentially affecting the validity of results.
• Another limitation of longitudinal research is that participants may drop out due to various reasons, leading to sample attrition.
• Sample attrition refers to the loss of participants during the course of a longitudinal study.
• Attrition occurs because some people are unable to participate at all stages of the study, while others leave the study early.
• In addition, there are challenges associated with collecting data at multiple points in time, such as participant burden (e.g., repeated assessments) and potential confounding factors (e.g., changing circumstances).
• Participants may drop out due to various reasons, such as moving away from the area, losing interest in the study, experiencing health problems, or becoming unavailable for follow-up assessments.
• To minimize sample attrition, researchers need to ensure adequate compensation for participation, maintain regular contact with participants, offer incentives for completing follow-up assessments, and address any issues that arise during the study.
• Participants who remain in the study over time may not represent the original population from which they were drawn.
• Another disadvantage of longitudinal research is that participants may drop out due to various reasons, leading to sample attrition.
• Participants may also change their behavior during the course of the study, potentially affecting the results.
• Participants may also change their behavior during the course of the study, introducing confounding variables into the analysis.
• Longitudinal studies:

  • Take place over a long period of time with the same participants
  • Intend to see how a certain stimulus affects participants over a specific period of time
  • Used to study developmental trends over time, often in child psychology
  • Many designs are observations and do not require manipulation of variables to make behavior observed as natural as possible
• Hankin et al (1998) study:

  • Aimed to see gender differences in how depression emerges in young people from pre-adolescence to young adulthood
  • Conducted a 10-year study using a birth year cohort
  • Used structured interviews 5 times over the 10 years
• Findings of the study:

  • More females emerged with depression than males at ages 13-15
  • Largest gender difference was between ages 15-18
  • No difference in depression rates between those who went to university and those who did not
  • No gender difference in the severity or frequency of depression
  • Increase in overall rates of depression and severity of symptoms occurred between ages 15-18
• Conclusion of the study:

  • Ages 15-18 are important for studying vulnerability to depression due to higher rates and large gender differences in depression at that time
• Evaluation of longitudinal design:

  Strengths:

  • Follow the same individuals over time to eliminate individual differences that might affect results
  • Valid way to study development without being subjected to individual differences
• Weaknesses:

  • Hard to keep participants in the study long enough to draw conclusions about their development
  • Potential bias if participants drop out or have differences in motivation
  • Potential ethical difficulties in following individuals over time, especially in mental illness studies
• Longitudinal designs involve collecting data over time with the same participants, allowing researchers to study how interventions affect participants over time
• Vallentine et al. (2010) used before and after measures with two questionnaires and a semi-structured interview at the end of the intervention
• They monitored participants for violent incidents at three and six months before and after a psycho-education training intervention
• Longitudinal designs are used to study developmental trends over time, often in child psychology
• Cohort studies follow one cohort of people over time, such as a school year group, to observe how characteristics or behaviors develop
• The length of a study doesn't determine if it's longitudinal, but rather following the same individuals over time and comparing changes
• Hankin et al. (1998) conducted a ten-year longitudinal study on gender differences in depression from pre-adolescence to young adulthood
• They used a birth cohort and structured interviews administered five times over ten years
• Between ages 15 and 18, there was a significant increase in depression rates and gender differences
• The study focused on the Dunedin Multidisciplinary Health and Development Study, following a complete birth cohort from New Zealand born between 1st April 1972 and 31st March 1973
• Data was collected at ages 3, 5, 7, 9, 11, 13, 15, 18, and 21, with a diagnosis of depression at ages 11, 13, 15, 18, and 21