Australia's Gambling Industries - Productivity Commission

(table F.2). However, coverage in the smaller states/territories was boosted to
increase statistical precision. Overall, the sample structure by area was very similar
to that used by the ABS for the Household Expenditure Survey.
While the original sample size for the National Gambling Survey was 10 500
respondents, interviews were actually completed by more than 10 600 participants.
The larger than originally specified number of respondents was needed in order for
all minimum quotas in the 120 area/age/gender cells to be met (see section F.7).
Table F.2
Distribution of national sample by geographic area
Population share (18+) %
Sample distribution (No.)
State/Territory Metropolitan Country Metropolitan Country Total
NSW 62 38 1 620 980 2 600
Vic 73 27 1 605 595 2 200
Qld 46 54 684 816 1 500
WA 74 26 813 287 1 100
SA 74 26 742 258 1 000
Tas 42 58 334 466 800
NT 42 58 252 348 600
ACT 100 - 700 - 700
Total 62 38 6 750 3 750 10 500
F.6 Procedures for selecting respondents
Two features of any survey are the coverage and the degree of non-response. As
noted by Steel, Vella and Harrington (1996):
Non-respondent units are selected in the sample but not measured, whereas noncovered
units have no chance of selection (p. 21).
While surveys generally aim to be representative samples of the general population
as a whole, there is a degree of non-coverage because some groups in the general
population tend to be excluded, such as:
• people in treatment settings, in hospitals, or in prisons; and
• the homeless.
With telephone surveys, a further element of non-coverage is that some households
either do not have a telephone or have an unlisted number. The former problem is
generally unimportant in Australia (though it may be relatively more important for
some groups such as problem gamblers who have had their phones disconnected
F.18 GAMBLING