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I'm writing an application that deals with blind studies. What would be the correct term to use when describing whether or not a study is blind? No matter which word I use it always ends up sounding awkward so I'm wondering what the correct term would be.

  • Blindedness
  • Blindness
  • Blind
  • Masked (?)

I am also looking for the opposite words, for example, is it correct usage to describe users as "blind/unblind" or "blinded/unblinded"?

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The study is either blinded or open-label. NB: the blinding can be single or double in nature. To describe the patients say: "Patient X was a member of the blinded group..." or "Patient Y received an open-label dose of drug-Z...". Don't say the patients themselves are blind unless they are and it's relevant. –  boehj Jun 6 '11 at 19:44

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up vote 5 down vote accepted

In light of the conversation I had this afternoon with my former boss, who actually conducts double- and single-blind studies, here is my revised answer. He also recommends using the specific type of blind experiment you employed.

In this single-blind study, a sample of fourteen participants tasted Coke and Pepsi.

Eighteen students participated in a double-blind study that compared apples and oranges.

It is unusual to describe users as blind (unless they are visually impaired). It would be more common to describe the trials as blind.

The participant completed a practice session, followed by a block of ten blind trials.

Otherwise, it is an open experiment (or open trials).

In a series of open trials, participants first ran to the water fountain and then were required to walk backwards while counting to fifty-seven by eights.

However, it is correct to say "blinded participant" and "blinded experimenter" provided that the context makes it clear that you are referring to the experimental paradigm and not the person's vision.

"Unblinded" can be used to describe someone who has knowledge of the experimental conditions, but it would be more likely to be used for someone who was "blinded" prior to the conclusion of the experiment than for someone who arranged the conditions during the experiment.

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"Blind" and "masked" are treated as synonymous by Clinicaltrials.gov, though I think I've seen "blind" more. I do not recall ever seeing "blindedness" or "blindness" in this context, and I agree that the trial is described as blind rather than the participants. We create constructions like "participants in the experimental arm of the study" instead. –  aedia λ Jun 6 '11 at 18:44
The example given by my boss was that the nurse giving the injections to the subject would be a "blind user" and that the data manager who oversees the randomization process between arms would be an "unblinded user". So "user" in this case is not necessarily a subject in the experiment. However, my boss is not a native English speaker so I am not sure if his terminology is correct. –  Lotus Notes Jun 6 '11 at 18:49
@Lotus Notes It sounds odd to me, but that's probably because if you know that it's a double-blind study, then you would also know that the nurse would be "blind" and that the data manager would not be. Let me ask around a bit and see if I can get you a better answer. –  Kit Z. Fox Jun 6 '11 at 19:00
I work with this terminology and frequently see "blinded" as in, "the study was properly blinded," or "similar results were obtained in the double-blinded trial." I've never seen "blindedness," probably because the state of a study being blind is binary - yes it is, or no it isn't. –  The Raven Jun 6 '11 at 19:12
@Lotus Notes @The Raven I asked my former boss, and he confirms that it is accurate to say "blinded participant" or "blinded experimenter" provided that the context is clear. He also mentions that "unblinded" could either mean that the data manager has known since the beginning of the experiment, or that the data manager was informed after the experiment was completed (provided that proper coding/decoding techniques were used). I'll amend my answer tonight when I have more time. –  Kit Z. Fox Jun 6 '11 at 20:04

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