Casino data literacy
The denominator changes the story
Methods, definitions and practical checks for reading casino reports. Turn a headline statistic into an answerable question.
Find who is counted
A percentage needs a denominator. In a hypothetical study, thirty people out of one hundred adults is thirty percent of all adults. If only fifty of those adults took part in the activity being discussed, the same thirty people would be sixty percent of that smaller group. Neither percentage is wrong, but they answer different questions.
Read the table notes
The Gambling Commission's guidance for the Gambling Survey for Great Britain emphasises the population behind each estimate. Some questions concern all respondents, others people who gambled within a stated period, and some online respondents only. A headline that drops that distinction can substantially change the reader's interpretation.
Carry the context forward
When quoting a result, preserve the age range, geography, reference period, sample base, and any exclusion such as lottery-only participation. Use the published uncertainty information where provided. For an article about casino participation, check that the table actually measures casino activity rather than treating all gambling participation as the same thing.