# Sampling methods

## Probability and non-probability sampling methods

The

Probability sampling allows for researchers to assume that any differences at baseline between

Non-probability sampling allows for researchers to study rare outcomes, generate hypotheses, establish prevalence, and create measures of odds and risk in patient populations. Causal effects cannot be inferred from non-probability sampling methods because of selection and observation biases associated with convenience and purposive sampling.

**fundamental difference**between sampling methodologies is the use of**.**__random selection__**or random selection of participants from the population of interest is used in**__Probability sampling____designs.__**experimental**__N__**is used in**__on-probability sampling__**studies where study participants are not chosen at random but outcomes are available for retrospective or prospective analysis.**__observational__Probability sampling allows for researchers to assume that any differences at baseline between

__groups is due to chance. Probability sampling further helps with the effects of confounding for both measured and unmeasured variables. Probability sampling is necessary in experimental designs that want to make causal inferences regarding treatment effects. With random assignment, groups are thought to possess a state of equipoise or equal levels of prognostic, confounding, and demographic characteristics at baseline between groups.__**randomly assigned**Non-probability sampling allows for researchers to study rare outcomes, generate hypotheses, establish prevalence, and create measures of odds and risk in patient populations. Causal effects cannot be inferred from non-probability sampling methods because of selection and observation biases associated with convenience and purposive sampling.

__and__**Quasi-experimental**__can yield stronger evidence.__**randomized designs**### Probability or non-probability sampling

Probability sampling methods include

__simple random sampling__**,**__stratified random sampling__**, and**__clustered random sampling__**.**## Hire A Statistician

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