A historical survey chart can explain a research question without describing today’s entire population. A Penang Green Council report labels its composting findings as 2015 fieldwork. Its reasons chart is especially easy to misuse: the bars should not be added into a count of Penang residents, and a later upload path does not make the underlying responses new.

Identify the year of the observations

The chart read for this article attributes fieldwork to 2015. The web address includes a later upload directory, but that is not evidence that the survey was repeated. Keep the fieldwork year attached to every statement about the responses.

A 2026 article can discuss what an older chart means while making clear that it is historical. It cannot call the figures a current composting rate without newer research. The original observation date matters more than a recent search crawl or the date you downloaded the file.

Read the reasons as labelled

The chart for respondents who did not compost lists lack of space at 56.5%, lack of knowledge at 49.4%, insufficient time at 37.2% and perceived complexity at 28.5%. These are reported reasons within the chart’s stated group. They are not established here as shares of all Penang residents.

The four numbers add to 171.6%. That arithmetic does not, by itself, prove an error. It also does not prove the exact questionnaire design. To interpret overlapping reasons or different denominators, the response instructions and methodology must be examined.

Do not turn a reason into a cause

A respondent’s reported reason explains what the survey recorded them saying. It does not independently establish that removing that obstacle would cause them to compost. A programme designed around one bar still needs a separate evaluation of what happens after support is offered.

For example, a space-related response can motivate a question about practical constraints. It does not identify which housing types were involved or prove that every household in those buildings lacks space. The excerpt does not support that geographical or housing-level conclusion.

Use the chart to frame a new question

A community organiser could ask which constraints participants currently describe and how those answers are collected. Record whether respondents can select more than one reason and which group each percentage refers to. That information makes a later comparison less ambiguous.

Do not compare percentages across years until the questions, sampling and denominators are compatible. A change in questionnaire wording can change the results even when behaviour does not. The report describes its sampling method, but this article does not independently audit the sample or adopt its representativeness claim as a current population estimate.

Evidence boundary

The PGC report’s chart and explanatory text were read on 20 October 2026. The report describes 2015 fieldwork and 1,484 responses; neither its sampling claim nor the reasons chart establishes a current 2026 population rate. This is a guide to a historical Penang evidence problem, not a current prevalence estimate.

Related Penang guide: Penang’s MAMPAN directory: choose the material before choosing a drop-off point.