A question such as “How happy were you with the quality of service at our restaurant?” seems reasonable on its face. But does the researcher mean happy? Or satisfied? And service, in terms of what? Why not ask several questions for each dimension of quality service. For instance; “How clean was our restaurant?” and “How prompt was the server in re-filling drinks?” See how “clean” and “prompt” are two different ideas and, more importantly, how one customer may think about cleanliness while another thinks about drink refills when trying to answer the original question?
So let’s assume you’ve settled on speed of service as what you’d like to gather customer feedback on. Since I’ve already written in this space that agree/disagree response options are not ideal, you may be tempted to ask something like “How satisfied were you with the promptness of the wait staff?” But this phrasing has induced an extra step, translating promptness into a more abstract feeling of satisfaction. A better approach is to rate the speediness of food and drink delivery straight away. In this way, we might ask “How prompt were the wait staff serving you?”
Check back here for a post on the various types of constructs there are in the world.