Table 5 Interview topic guide.

From: Colour vision deficiency and sputum colour charts in COPD patients: an exploratory mixed-method study

Interview questions
1. How would you describe the different colours on the colour chart in front of you?
2. Are there any parts of the chart where it is hard to tell the difference between the colours?
3. If you needed to do this on your own, how confident would you be in reading the chart with no assistance?
4. How much would you trust using this colour chart to be accurate, or would you want to check with a doctor or health professional?
5. What are some of the reasons why people might want to use a colour chart?
6. What are your thoughts on each of these reasons?
7. Can you anticipate any problems using it in this way?
8. What would you say is the best bit of it and the most challenging part of the chart to use?
9. Would anyone like to add anything else now?