Week 2 Flashcards
3 basic mixed method designs
Sequential explanatory - quantitative then qualitative
Sequential exploratory - qualitative then quantitative
Convergent, simultaneously or concurrent triangulation
Cross sectional studies
Conducted at a single point in time or over a limited time period
Carried out to estimate the prevalence of the outcome of interest within the population
‘Snapshot’ of the outcome and the characteristics associated with it
Cross sectional studies advantages
Relatively inexpensive and takes up little time
Can estimate prevalence of outcome of interest because sample is usually taken from the whole population
Many outcomes and risk factors can be assessed at the same time
Useful for public health planning understanding disease aetiology
There is no loss to follow up
Longitudinal Studies
Similar to cross sectional studies but a group of people is followed over time
Used to estimate the incidence of a health state in a defined population
Experimental studies
Can be defined as truly scientific if they display certain characteristics consistent with method:
- quantitative nature
- methodology well defined
- methodology is reproducible
- generation of hypothesis
- variables are controlled/manipulated
- accurate measurement and quantification of data
- findings can be generalised to similar populations
Cohort studies advantages
Temporal dimension, whereby exposure is seen to occur before outcome, gives indication of causality
Can be used to study more than one outcome
Well suited for the study of rare exposures
Can measure the change in exposure and outcomes over the time
Incidence of outcome can be measured
Case control studies advantages
Allows the assessment of causation when the outcome is rare or take a long time to develop
Includes a control group
Numeric variables
Can be differentiated as discrete or continuous
Discrete variables
Uses only whole numbers - counting
Continuous variables
Can present some values in between units
18.6Kg, 1.83m etc
Categorical variables
Can be differentiated as nominal or ordinal
Nominal variables
Have no natural order - gender, country, etc
Ordinal variables
Rank ordered - satisfaction rating scale 1-4
Sample
A reference group for drawing conclusions about the population
The larger the sample size the less the sampling error
Probability methods for drawing random sampling
Random Systematic Stratified random Disproportionate Cluster
