eitodennäköisyysotokset

Eitodennäköisyysotokset, known in English as non-probability samples, are a method of sampling where the selection of individuals is not based on random chance. Instead, the researcher uses their judgment or other non-random criteria to choose participants. This approach differs from probability sampling, where every member of the population has a known, non-zero chance of being selected.

There are several types of non-probability sampling. Convenience sampling involves selecting participants who are readily available and easily accessible. Quota sampling aims to create a sample that mirrors the proportions of certain characteristics (like age or gender) found in the population, but the selection within these quotas is non-random. Purposive sampling, also known as judgmental or selective sampling, involves the researcher using their expertise to select participants who they believe are most representative of the population or possess specific relevant characteristics. Snowball sampling is used when the population is difficult to access, where existing participants recruit further participants.

Non-probability sampling is often employed in exploratory research, qualitative studies, or when probability sampling is impractical or too expensive. It can be faster and more cost-effective. However, a significant limitation is the lack of generalizability. Because the sample is not random, it is difficult to confidently infer findings to the entire population. There is a higher risk of sampling bias, where the selected sample may not accurately represent the diversity of the population. Therefore, researchers must be cautious when interpreting and reporting results obtained through non-probability sampling methods.