Showing PDF instead of image SurveyCTO

Hi everyone!

New to the forum! I have searched in the forum but could not find a good solution to this issue so I thought it's worth asking.

In a nutshell, we want to show respondents a randomly selected document as part of our questionnaire. We are replicating those studies that show randomly generated CVs to identify possible cases of discrimination, but using other type of document.

For this, the solution we can think of using SurveyCTO is the following:

  1. First, upload a set of randomly generated documents along with the survey form
  2. Then, in the questionnaire, select a random document out of those uploaded and show it to the respondent as a question. The set of documents to select from is constrained by the respondents characteristics (firm's sector basically). So we'll probably first calculate the name of the file to be opened then tell SurveyCTO to show the file with that name.

The problem is that we may have thousands of documents and therefore we fear we may have a problem of storage and/or computing power. We have considered the following options:

  1. PDF documents: If we can upload documents as PDF instead of image, storage needs would be reduced, since these are one-page documents.
  2. Link to a PDF documents. An alternative to the above is to show a link to a pdf document stored in our tablet. After showing the pdf to the respondent, the enumerator goes back to the survey and continues with the next questions.
  3. Images: This is the easiest to implement, but we may fear it will not work, since images take a lot of storage. We expect several thousand images, and at 1mb that's several GBs.

So, my questions boil down to:

  • Is there any way to show pdf as part of the questionnaire? (option 1)
  • If not, is it possible to include a link to a file in the internal storage? (option 2)
  • Overall, do you expect issues for SurveyCTO to store and access thousands of images as part of a survey's attached media?

We have still not tested these options but we'll try to do it soon.

Thank you so much for your help!

P.D:We are using SurveyCTO and SurveyCTO collect, version 2.60.01

HI @jadelcar! SurveyCTO is based off ODK tools, but has deviated substantially. Because it's closed source, we really don't know how much it has deviated. If you have questions about SurveyCTO, please ask at

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