Cross-sectional Studies

• Cross-sectional studies:

  • Simplest form of observational study
  • Describes population at one point in time ‘snapshot’
  • Exploration of factors associated with a disease or condition (risk and/or protective factors)
  • Can compare subgroups within a population
  • Typical research question “What proportion of the population have characteristic X?"
• Typical cross-sectional study questions:

  • What are the characteristics of this population?
  • What proportion of the population have characteristic X?
  • Do people with characteristic X differ from those who don’t?
  • What variables are related to characteristic X?
• Important to consider the temporal association between exposure and outcomes:

  • cross-sectional study occurs in the present, where we're observing exposure and outcome at the same time, so we cant tell if the exposure caused the outcome, we just know they existed at the same time
• Cross-sectional studies:

  • Strengths
  • quick to conduct, relatively cheap
  • allows exploration of multiple risk factors
  • useful to assess health needs of population
  • useful first step: hypothesis generating – may provide clues & justification for further investigation
  • Weaknesses
  • selection bias (selection of sample, responders etc)
  • cannot prove cause – single point in time (snapshot)