As market researchers, we are frequently asked to assess the opinions of our constituents. In the process of questionnaire creation, this can take the place of asking one group directly about their sentiment, but there are other options. It is equally common to ask one group about their perceptions of what another group might think. The example below asks market researchers to provide an assessment of what their internal clients find important.
This approach to questionnaire development is certainly valid, but it does leave the door open for error. This technique would be used when we do not have access to the other party to solicit their opinions. However, anytime we ask one group to respond while wearing the hat of another group, there is the potential to over or understate opinions.
A better approach is to survey both groups using the same questions. This allows for one to one comparisons and makes it easier and more effective to identify gaps in perception. An example would be to survey sales reps and their customers in order to assess satisfaction with the sales process. Another common approach is to survey both current customers and non-customers to assess brand awareness and likelihood to purchase (repeat for existing customers and first-time purchase for prospects). This latter case also allows for a comparison of attitudes toward the company and key competitors.
This second approach hinges upon having access to the second group, either through existing contact information, as in a prospect database, or through the use of a survey panel.
In summary, it is best if you can assess the opinions of two (or more) groups directly in a side-by-side comparison. If this cannot be done you can fall back to having your primary group estimate the opinions of others, e.g. sales reps speaking for clients, but be aware of potential error.