eVAS 4+

Electronic Visual Analog Scale

Ryan Tennant

    • Free

iPad Screenshots


The Electronic Visual Analog Scale (eVAS) is an ad-free iPad app that allows users to digitally track visual analog scores using 10 cm slider channels with various customizations and export saved data in tables. It can be used as a pain scale tracker or for any other application that requires user input tracking on a 10 cm visual analog scale.* eVAS was designed and developed in 2023 by Ryan Tennant in partnership with the Biomechanics and Injury Prevention Lab at the University of Waterloo. Funding for this app was provided through the Centre of Research Expertise for the Prevention of Musculoskeletal Disorders (CRE-MSD) that receives funding through a grant provided by the Ontario Ministry of Labour, Immigration, Training and Skills Development.

We provide our users with various customizations unique to eVAS. Users can customize their collection settings by:
- choosing one of three default images or uploading an image from their device to be stored locally,
- specifying a session identification label,
- setting left and right anchor label text,
- selecting among 1-22 collection channels to record visual analog scores,
- setting a recurring alert reminder within the app, and
- exporting their data in .CSV or .XLSX format via e-mail or other file-sharing methods available on their device.

Find the complete instructions and other information on using eVAS under the info icon on the Collection Settings screen.

*The slider length is 10 cm — output scores range from 0 to 1 for each channel with a precision of 6 digits. The 10 cm visual analog scale and threshold values for clinically relevant pain have been previously evaluated in clinical research applications with humans, such as detecting clinically relevant low back pain [1,2]. The design of eVAS employs the 10 cm scale that has been validated in peer-reviewed literature [1-5]. Its design is further informed by current research validating the reliability and accuracy of clinically relevant pain using visual analog scales through touchscreen devices [3-5].

[1] https://pubmed.ncbi.nlm.nih.gov/24384659/
[2] https://pubmed.ncbi.nlm.nih.gov/12592542/
[3] https://pubmed.ncbi.nlm.nih.gov/26769149/
[4] https://pubmed.ncbi.nlm.nih.gov/30211382/
[5] https://pubmed.ncbi.nlm.nih.gov/12237213/

Medical Advice Disclaimer:

The Contents of the App is for data collection and informational purposes only. No material on this app is intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen or making any medical decisions, and never disregard professional medical advice or delay in seeking it because of your use of eVAS.

What’s New

Version 1.0.3

Minor bug fixes & improvements:
* Ensures only alpha-numeric characters, hyphens, or underscores are included in the file name when exporting data

App Privacy

The developer, Ryan Tennant, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More

You Might Also Like

QOR360 FitterSitter
Health & Fitness
Health & Fitness
Purdue Pegboard Scoring
Health & Fitness
Alarm Clock – Wake Up Time LTE
Health & Fitness
Kegel Kounter
Health & Fitness
Polar GoFit
Health & Fitness