research sampling methods - white paper - market research consultants - latimer appleby
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7/30/2019 Research Sampling Methods - White paper - Market Research Consultants - Latimer Appleby
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Research Sampling Methods: A LatimerAppleby Useful Guide
Research sampling is really about how we decide who we are going to talk
to; it is an essential ingredient of market research - it is the part which laysdown the selection of individuals who will be asked to supply the requiredinformation. Various methods can be used, but the method used should bethe most effective and efficient for the collection of the required data. Thesample should be large enough to give statistically significance to theresults obtained for the smallest group required for examination. Here agood rule of thumb is to work on the principle of a minimum of 100respondents per sub group (or cell) that you want to analyse. For example,if you wanted to examine potential differences between six different agecohorts: 18-24 year olds; 25-34 year olds; 35-44 year olds; 45-54 year olds;
55-64 year olds; and those aged 65 or over; you would require a sample of600 respondents.
We use two main forms of research sampling: random sampling and quotasampling.
Random sampling
Here every item in the universe (i.e. your chosen target group) to besurveyed is given a single and equal chance of being selected with everyunit of the universe being included. As we might guess, there are strengths
and weaknesses of random sampling.
Pros
No advance knowledge of any characteristic of the universe is required Sampling biases can be pre-determined Small minorities in the universe can be represented with the correct size
of the total sample
Cons
The universe to be sampled must be unique Mistakes are easy to make and maybe difficult to detect Geographic spreads of the pure random sample can be extremely wide,
with resultant contact difficulties and expense
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Quota sampling
A quota research sample is one in which the known proportions of major
characteristics as they appear in the universe are deliberately made toappear e.g. housewives, certain age groups, people who have decoratedtheir homes within the last 12 months.
Pros
No essential sub group can be accidentally omitted Interviewer biases can be minimised by more exact instructions Greater geographical concentration is possible Sample errors are no greater than for a random sampleCons
Detailed data about the characteristic proportions in the universe isnecessary
Interviewer dishonesty in informant description is not always easy todetect
Minority sub groups may be over weighted
Which research sampling type should be used?
There is no right or wrong answer, but random sampling is principally usedwhen you want a broad picture or have little knowledge about the area ortarget group being investigated.
Quota sampling is used when you know who you want to talk to
and do not want to waste money talking to the wrong people.
Need help choosing the right research sampling method for you? Feel freeto contact us.