Research methods

Cross sectional study

Measuring the prevalence of something in a population

incidence

refers to the occurance of new cases or injury over a specified period of time

prevalence

the proportion of persons in a population, counting something that already has happened.

Epidemiology 

studying disease, distribution and patterns of a disease.

Randomised controlled trials

Participants randomly allocated, the strongest design for causality

Cohort study

Follows a group of people over time to see how different exposures affect who develops a particular outcome or disease

Strengths of cohort studies

• clear time sequence

• Less recall bias

• Captures multiple exposures and outcomes 

weaknesses of cohort studies

• cost

• Follow up and retention

• Potential confounding

strength of Cross sectional studies

• inexpensive

• Easier/faster to do

• Capture multiple exposures and outcomes

weaknesses of cross sectional studies

• confounding

• Uncertain time sequence

RCT strengths

• Good evidence that intervention leads to outcome

• Randomisation

weaknesses of RCT

• cost

• Participants may leave

• Ethical limitations

• Hard to follow up long term

Confounding

something other than what your measuring affect the outcome