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Overview	Setup	Distribution	Precautions

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Overview

Public Survey Links within REDCap are single survey links that can be used repeatedly to create new records and survey responses each time a survey is completed using the link. Unlike normal survey distribution links that are specific to a record within a REDCap project, public survey links can be used more than once and function as a tool to help distribute the REDCap survey to many people. 

Public surveys cannot be linked to an existing record.  They will continue to make a new participant record each time. 

Common use cases for Public Survey Links:

• Study Interest / Recruitment Form
• Eligibility Intake Form
• Anonymous Survey Collection

If your first data collection is enabled as a survey, then you may use a public survey link, which is a single link that can be emailed to all participants or even posted on a website or flier.

Only ONE public survey link is available per project.  If your project is longitudinal, then you will have access to one public survey link per project Arm. 

Public surveys on most platforms run the risk of experiencing survey fraud.  For more information on handling survey fraud within REDCap, see our section on Precautions

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Public Survey Setup

A Public Survey can be enabled in a REDCap project using the steps below:

• Under Project Setup - Main project settings, select "Enable" for "Use surveys in this project?" 

• In the Online Designer, create your Public Survey instrument and enable the instrument as a survey

• Set your Public Survey as the FIRST data collection form of the project. 
  • If you are also using a longitudinal project then this must be the first form in the first event.

• Go to Survey Distribution Tools under Data Collection in the left-side applications menu to find a copy of your Public Survey link

Longitudinal Projects

Since the FIRST form of a REDCap project MUST be the survey in order to obtain a public survey link, the project may need pseudo a "landing page" as the first public survey instrument. This landing page instrument can be mostly instructional or have some information provided while not collecting data as a starting focal point for ALL arms.

Based on responses or the structure of the arm itself, this landing page survey can then properly auto-continue to the next arm specific survey.  

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Distribution Options

Public surveys are primarily distributed using the Public Survey URL found under Survey Distribution Tools. 

Once a public survey has been created as the first project instrument, the URL will populate and can be copied and shared.  Sharing this survey link will allow anyone to complete a new copy of the survey and create a new project record each time.  

Since public surveys are open and shareable, there is the risk of the survey being shared and completed by people who should not be accessing the survey and/or by spam bots submitting false responses. Distribution of the survey link should be handled with care following our recommendations. 

We recommend NOT including information about monetary compensation on online fliers, advertisements, or posts. (e.g. 'complete this survey for a $XX gift card' on a public posting/flier)

See the below section on Precautions

For fliers or other physical or digital media distribution a QR code is available.  Under Survey Distribution tools, select "Survey Access Code or QR Code" to find your project QR code and have the option to copy or download a SVG copy of the QR code. This code may be printed on physical media or embedded on websites as needed.  This will allow potential survey respondents to scan the code with their smartphone and complete the survey from their personal device. 

Under this same window, there are options for distributing the REDCap public survey using an Access Code.  This distribution method requires an additional code to be shared that will grant them access to the survey while using the generic https://redcap.ictr.wisc.edu/surveys/ link. A temporary code may be used instead that will expire after a single use and after 1 hour has passed. 

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Precautions and Considerations

There are several issues that REDCap projects may encounter when using Public Survey links from people developing ways to exploit surveys via the available links. This is particularly a concern for public survey links which may provide opportunities for monetary compensation.

Common Motivations for Survey Fraud:

• Financial Gain - Taking advantage of a reward
• Disruption / Harm - Causing damage or disruption
• The Challenge - Doing it simply because it can be done

Below are a few options to manage or mitigate risk of your survey being targeted by bots. 

Make a plan for survey distribution:

When public surveys are to be used in a project, the study team should be proactive in making plans to limit risk / exposure.

• Determine if public surveys are actually“necessary” to accomplish the goals of the study.
• Have a plan for distributing the survey link and where the link will be sent or displayed. 

Monitoring the Database:

Develop a strategy for monitoring the database:

• Watch for duplicate survey responses
• Watch for a sudden increase in rate of survey responses
• Designate responsibility to monitor incoming survey responses to an appropriate team member.
• Schedule reviews records in batches and set a timeline for when reviews should happen

If your survey has monetary compensation, set a break-point to manually review survey responses before payment. Do not set-up an automated payment system before staff review. 

Survey Design Strategies:

• Consider a “Response Limit” to cap the number of survey responses (Under Survey Settings)
• Implement Challenge questions
  • Questions that have a correct answer or a directed answer to exclude survey responses that do not give the correct response. 
  • Example:  "Select choice number 3 for this question"
• Add “Honeypot” questions
  • Questions that are hidden on the form (by branching logic or @HIDDEN-SURVEY Action Tag) that bots could access but a normal participant could not. 
  • Example: "This question is hidden, and should not have a value"
• Include “repetition”
  • Repeated or similar questions that should give a similar response for a real participant but bots may answer randomly.
  • Example: "How much do you like strawberries?",    "How much do you enjoy strawberries?"
• Paradata collection analysis
  • Data or statistics stored with surveys in REDCap that can be used to detect bot responses.
  • Survey Start Time Smart Variable - [survey-start-time]
    • Look for clusters of surveys occurring at the same or similar times.
    • Look for patterns (is there a bump in submissions at a similar time every day/night?).
  • Survey Duration Time  Smart Variable- [survey-duration]
    • Enter a few test surveys to create a range of “reasonable” times for completion.
    • Are surveys being fully completed in an very short (unrealistic) time-frame?

We recommend NOT including information about monetary compensation on online fliers, advertisements, or posts. (e.g. 'complete this survey for a $XX gift card' on a public posting/flier)

Google reCAPTCHA

The Google reCAPTCHA feature can be enabled to help protect your public surveys from abuse from 'bots', which are automated software programs that might enter trash data into your survey. A 'captcha' is a test to tell humans and bots apart. By enabling Google reCAPTCHA on your public survey, you can block automated software while helping welcome your survey participants to begin your survey with ease.

More on reCAPTCHA: https://kb.wisc.edu/smph/informatics/111364

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If you have a UW-Madison REDCap project and have questions about Public Survey Links, please send them to REDCap@ictr.wisc.edu

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