Longitudinal and cross-sectional studies Flashcards
What is a longitudinal study or design?
It is a study conducted over a long period of time in order to observe long-term effects for example the difference between people of different ages
What is a cross sectional study or design
This is where one group of participants at a young age are compared to another old group of participants at the same point in time with a view to investigating the influence of age onthe behaviour in question
What is a snapshot study
This is a term often used for a cross-sectional study because it is a snapshot taken at a particular moment in time
What are cross-sectional or snapshot studies used for
They might be used to look at the behaviours of different professional groups e.g. teachers or doctors i.e. different sections of society
What are the strengths of longitudinal studies
Participant variables are controlled
What are the strengths of cross-sectional studies
They have the advantage of being relatively quick
Name a weakness of a longitudinal study
Attrition is the main problem some of the participants inevitably drop out over the course of the study
What is the problem of attrition in a longitudinal study
The sample that is left may be biased or too small (this is because those who are less motivated or with particular personal characteristics are likely to leave)
How might participants behaviour be affected in a longitudinal study
They become aware of the research aims and their behaviour may be affected as a result
Why might financing a longitudinal study be difficult
Because the studies take a long time to complete and can be expensive or difficult to obtain a sponsor
Why are differences in a longitudinal study due to participant variables rather than the independent variable
Because participants may differ in more ways than the behaviour being researched e.g. when comparing teachers doctors and solicitors teachers behaviour may differ because they have less money
What are cohort effects
These occur because a group or cohort of people who all the same age share certain experiences such children born before World War II
are the findings of one cohort in a longitudinal study generalisable
No because of the potentially unique characteristics of one cohort
Give an example of a cohort effect in a cross sectional study of IQ
The IQs of twenty year old might be compared with 80 year olds - finding that the IQ of the latter group was much lower. Although this suggests that IQ declines with age however it might be due to something else for example that the 80 something had lower IQs when they were 20 due to e.g. poorer diet
