Adding a special response (DK/NA) to a textbox question


I have a numeric response where I also need to add an option for a respondent to specify a ‘Don’t know’ response. Ideally I would like validation that one of either the numeric response or the DK response has been answered (and that both have not been answered).

I have set up a Custom Group style question but it expects/forces additional question text above the single DK checkbox that I just wish to sit below the textbox. I’ve added a non-visible bit of html to the question text to hide it but it all seems rather inelegant for what I expect would be a simple operation. Additionally there is no validation so a respondent could type in a numeric response and check the DK option. I added skip logic to redirects back to the question if DK and textbox are missing a response and also if both DK and textbox have been answered. Works ok but doesn’t give the respondent any error validation.

I’ve also tried a custom table that gives me a similar but horizontal layout but that doesn’t have required validation within the subquestion (e.g. to check numeric response is entered within the allowed range in the textbox).

Am I missing something obvious? Does anyone have any best practice/solution/advice?

Ben answered
    Ben 33 Rep.

    This example needs tidying up a little but it demonstrates the functionality I put in place with a bit of survey logic and a bit of custom scripting:

    Because SurveyGizmo does not accept same page negative logic I was unable to display a message for a situation where both the numeric and the checkbox were left unanswered. That makes sense in this case as the initial state would trigger it and this can only be checked on submission.

    Wish there was an in built option to simply add a ‘special response’ (DK/NA) to a text box though!

    Ben commented
      • Ben – This is AWESOME. Wow! Thank you! Can you help me to replicate that?

      • Hi Rebecca – only just seen this so very sorry for late reply. Let me know if you still want to replicate and I’ll try and figure out how to share it with you!


      I’d do this as a radio button question. So for example you could set it up as:

      In what year were you born?

      • Enter year ____
      • Don’t know

      To make this work, you have to set the first response as “Other – Write In” (or “Other – Write In (Required)”). You do this by clicking on the little pencil next to the response option in the edit window, and then choose the option you want under “Special Settings.”

      Then, on the validation tab, you can set it to require a numerical answer.

      Ben commented
        • Thanks for the response. That does functionally work on a single numeric question requiring a DK response. You could further tighten this up by having the option pre-selected and my only slight issue is that it looks a bit inelegant. But it’s a good suggestion and easy to set up.


        Hi Ben,

        You could also use the AUTO SUGGEST validation method (  You could enter the exact values that your respondents will be entering as well as a DON’T KNOW response.  Since the AUTO SUGGEST feature restricts your respondent’s input to what you place in the list you will not have to worry about a conflict between responses to two different questions.

        We am making some assumptions about the values that your respondents will be entering.  If you could provide some more information about your question, your fellow users can provide you with better guidance.

        Jim W (Moderator) edited answer


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