The Five Don'ts of Questionnaire Design 1. Don't ask too many open-ended questions. Keep them to a maximum of three. Many respondents skip such questions. When conducted over the phone, you would just get dead air.
Consumer behaviour is in different shades of grey.
You use research to find these shades. Don't combine two questions in one. Don't ask factual questions that require respondents to look up records and invoices to report exact amounts. Don't use jargon and slang. Customers might not be familiar with the language you use in your organization.