In particular, I think “Almost always have just one question per page” and not using sliding scales rather than lists, seem like things I would not generally recommend (although having one question per page and using lists rather than scales is often fine).
Do you have any heuristics for when just one question per page is better, worse, or equally good as many questions per page?
(No worries if not—I can also just ask you for private feedback on my specific survey.)
I think it depends a lot on the specifics of your survey design. The most commonly discussed tradeoff in the literature is probably that having more questions per page, as opposed to more pages with fewer questions, leads to higher non-response and lower self-reported satisfaction, but people answer the former more quickly. But how to navigate this tradeoff is very context-dependent.
All in all, the optimal number of items per screen requires a trade-off: More items per screen shorten survey time but reduce data quality (item nonresponse) and respondent satisfaction (with potential consequences for motivation and cooperation in future surveys).Because the negative effects of more items per screen mainly arise when scrolling is required, we are inclined to recommend placing four to ten items on a single screen, avoiding the necessity to scroll.
In this context, survey researchers have to make informed decisions regarding which approach to use in different situations. Thus, they have to counterbalance the potential time savings and ease of application with the quality of the answers and the satisfaction of respondents. Additionally, they have to consider how other characteristics of the questions can influence this trade-off. For example, it would be expected that an increase in answer categories would lead to a considerable decrease in data quality, as the matrix becomes larger and harder to complete. As such, in addition to knowing which approach leads to better results, it is essential to know how characteristics of the questions, such as the number of categories or the device used, influence the trade-off between the use of grids and single-item questions.
But, in addition, I think there are a lot of other contextual factors that influence which is preferable. For example, if you want respondents to answer a number of questions pertaining to a number of subtly different prompts (which is pretty common in studies with a within-subjects component), then having all the questions for one prompt on one page may help make salient the distinction between the different prompts. There are other things you can do to aid this, like having gap pages between different prompts, though these can really enrage respondents.
Do you have any heuristics for when just one question per page is better, worse, or equally good as many questions per page?
(No worries if not—I can also just ask you for private feedback on my specific survey.)
I think it depends a lot on the specifics of your survey design. The most commonly discussed tradeoff in the literature is probably that having more questions per page, as opposed to more pages with fewer questions, leads to higher non-response and lower self-reported satisfaction, but people answer the former more quickly. But how to navigate this tradeoff is very context-dependent.
https://www.researchgate.net/publication/249629594_Design_of_Web_Questionnaires_The_Effects_of_the_Number_of_Items_per_Screen
https://sci-hub.ru/https://journals.sagepub.com/doi/full/10.1177/0894439316674459
But, in addition, I think there are a lot of other contextual factors that influence which is preferable. For example, if you want respondents to answer a number of questions pertaining to a number of subtly different prompts (which is pretty common in studies with a within-subjects component), then having all the questions for one prompt on one page may help make salient the distinction between the different prompts. There are other things you can do to aid this, like having gap pages between different prompts, though these can really enrage respondents.