Friday, November 27, 2015

The Problem with Asking Respondents to Respond Using a 1 to 10 Scale

 How often have you seen a survey question that requires the respondent to indicate their opinion by selecting a number between 1 and 10?

Such question formats are not that surprising as it is very common for people to be verbally asked their opinion by being asked to score something from 1 to 10, so why when designing surveys is using a scale in any way wrong?

Asking someone to rate something out of ten is quite acceptable when the intention is to simply gauge a single individual’s opinion, or just to informally test the temperature of a group over a particular topic, but where the intent is to collate meaningful data it can at worse be flawed and at best convoluted.

So what is the problem?  


Some surveys commit a cardinal survey sin by using a response scale and not advising the respondent as to whether 1 is to be scored low or high causing all the data being collated to be flawed as there is no way of knowing how many people will have answered thinking 1 should be scored high and how many the opposite, so the first rule when using any type of numeric scale is to remove any ambiguity and state clearly as part of the question if 1 is to be scored high or low.

Why 1 to 5 is much better than 1 to 10 or 1 to 100

Regardless of how 1 is to be scored, there are however further considerations one of which is why have the numeric scale set from 1 to 10, or in some cases 1 to 100?

If when analysing survey responses such questions are nearly always divided into five distinct groups such as:
  • "Very Poor", "Poor", "Okay", "Good", "Excellent"
  •  "Strongly Disagree", "Disagree", "Neutral", "Agree", "Strongly Agree"
  •  "Very Satisfied", "Satisfied", "No Opinion", "Dissatisfied", "Very Dissatisfied"

If the collated information is going to be grouped into five distinct groups, it makes sense that the numeric scale is set from 1 to 5 rather than 1 to 10 or 1 to 100 as the scores are only going to be regrouped during the analysis stage.

But why use a numeric scale at all?

Since all numeric scales need to be clarified by associating the numbers to descriptive text, such as "Very Poor", "Poor", "Okay", "Good", "Excellent", why not just cut straight to the chase and use the text descriptions as unlike with numeric scales there is no ambiguity when text is used and there is no need for any further clarification.

In summary

  • If using a numeric scale make sure that you advise the respondent if 1 is to be scored high or low.
  • Unless there is a good reason to do so consider how the collated data is going to be analysed and reported and then seriously consider if using a numeric scale that is from 1 to 5 is better than using a 1 to 10 or 1 to 100 scale.
  • Unless there is a good reason to use numeric scales always consider if it would be better and less complicated to use text descriptions rather than numeric scales, especially if the text descriptions are going to be used in reports when analysing the collated data.

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