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| The author
of a text book, Henslin, wanted to make observations about homeless
people. |
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| His
method was participant observation. |
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| He wanted to
live with them and to experience what they experienced, and to find out
what they themselves thought about the meanings of what they were doing. |
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| He could not
live with more than one homeless group at a time, so his sample consisted
of only one community among the thousands that exist throughout North America
and the rest of the world. |
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| If we knew
for sure that every homeless community was radically different from every
other one, then the validity of his findings would be very low. |
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| If we believe,
as we do, that there are many similarities between those communities, his
validity would be very high, much higher, for example, than if he went
around with a clipboard asking questions from a questionnaire. |
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| (See that the
method and the sampling technique are not as unrelated as one might first
imagine both in combination contribute to the level of validity). |
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| The text book
gives an example of a population being all the students of a university,
and a sample being those interviewed with a questionnaire. |
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| How
do you choose that sample? |
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| Do
you ask every fifth person walking down a particular hallway? |
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| Will that bias
your sample towards students taking those subjects taught in the rooms
in that hallway? |
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| Would
that bias affect the results? |
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| If you were
asking questions where there might be significantly different answers from
students taking one subject, rather than another, then that method of sampling
would bias the result. |
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| He
suggests that a random sample would be most valid. |
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| So
how do you choose a sample that is random? |
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| Here
you might exercise your imagination, initiative and creativity. |
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| How
much a proportion of the population should the sample be so that it is
valid? |
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| If you interview
only ten people out of a population of several thousand, perhaps the results
would not be as valid as it might be if you interviewed a sample of one
thousand. |
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| My
PhD research was based mainly on participant observation. See Why
Obo? |
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|
