Screen by device

For my study I want to make sure participants are only using desktops and laptops. I know I can select that in the Study Details page, but it also says there that prolific won’t actually screen for this.

The devices and tool options will be displayed to participants on their study preview. These options don’t screen participants. To screen participants use the “Prescreen participants” option in the Audience.

Below that is a link to an article: Read about device compatibility, but this link is broken.

In the Audience: Prescreening menu there is not an option to screen by device type.

How do I make sure everyone taking my study is using a physical keyboard?

Dear Adam

There is no option for laptops, but you can specify desktops. There will be very few desktops that do not have keyboards.

I personally think it would be fair, bearing in mind that the device type is specified in the description, to prescreen INSIDE your study rejecting those that say they are not using a desktop, returning them to prolific with instructions to return their submission.

We are allowed to pre-screen in this way for questions asked in prescreening questions but I am not sure if the above is or is not against the TOS.

In my humble, non prolific employee, opinion.


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Thanks so much for this Tim. Sorry for the late reply; for some reason I’m not getting notifications from Prolific.

Unfortunately I don’t have the ability to screen inside my study, but I guess I can at least mention it in my description. I’ll also ask them in the post-test survey, and will be able to see if their keystroke timing looks weird.

You could also ask support for a new screener.

Audio, microphone, and camera are checkboxes on the study settings. If keyboard were there too you could eject people that don’t have one.

And, Googling I find, there is JavaScript to detect whether users are using a physical or virtual keyboard because “Virtual keyboards on mobile devices fire the events at physically impossible speeds.” Even if JavaScript is not an option, this blog post is interesting. The average time between keydown and keyup for physical, Android and IOs virtual, are >25ms, 12ms, and 10ms respectively.

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Thanks! My study is actually a keystroke study, and we’re already calculating keystroke timing. I hadn’t thought to use that as a proxy for what type of device they’re using.

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