Cross sectional/longitudinal studies

• Features of cross sectional research

  • A method used to investigate differences in ‘sections of society’, such a looking at differences between age groups, genders, socio-economic background etc.
  • Often referred to as a ‘snapshot study’ as you get to see a snapshot of people and their behaviour at one point in time.
  • Can also be carried out to investigate differences between different ‘groups’ of people e.g. different professional groups (teachers, doctors, solicitors etc)
  • Does not involve manipulation of variables
• Strengths of cross sectional research

  • quick and cheap as participants only need to be tested once for comparisons and no follow up study is necessary
  • participants easily obtained as there's less pressure for them to take part, compared to having to stick long term like longitudinal - larger sample size increasing population validity
• Weaknesses of cross sectional research

  • difficult to establish why there are differences between two cohorts as participants cannot always be asked about the differences, this may be due to participant variables and so lowers internal validity
  • data collected is from a snapshot in time so its harder to identify and analyse developmental trends in these studies, makes it difficult to generalise findings
• Key features of longitudinal

  • A method where research carried out over a long period of time
  • It involves identifying one group of participants and study them at various intervals over a period of usually several years.
  • Used to observe long term effects on people 
  • E.g - to see how people change/develop (Developmental Psychology)
  • It involves using a range of methodologies to collect data- observations, case studies, interviews
  • Does not involve any manipulation of variables
• Strengths of longitudinal

  • same person tested numerous times so participants variables are controlled = increases internal validity
  • developmental trends can be spotted easily as test repeated at regular intervals, findings are compared = reduces recall bias - participants researched as their life occurs rather than asking them to report what happened a long time ago = u=increases internal validity
• Weaknesses of longitudinal research

  • high attrition rate because the researcher takes so long, sample left small which makes it a biased sample
  • participants are more likely to be aware of aims of study and so they may show demand characteristics