My wife bought new toothbrush heads on her way home from work today.

They didn’t fit. She bought the “Oral B IO” heads, but we have a “regular” Oral B toothbrush, not the Shiny Fancy IO design.

And this is after she bought replacement heads last week at another store – which turned out to be “compatible for” a different brand :(

Ugh.

  • iamthetot@piefed.caEnglish
    3·
    2 days ago

    Can it not still be double blind if the participants don’t know precisely what is being measured or studied? For example, perhaps they know they are involved in a toothbrush study, but not that one group will have different brushes, or precisely what measurements are being taken.

    • elephantium@lemmy.worldOPEnglish
      1·
      1 day ago

      No. Double blind means that both the researchers and the participants don’t know who is in which group (control group or experimental group). The idea is to avoid spoiling studies with the placebo effect.

      It’s kind of hard to avoid knowing that you’re in the control group when you’re being asked to brush with an old-fashioned toothbrush instead of an electric one.

      • iamthetot@piefed.caEnglish
        2·
        1 day ago

        Decided to do some reading!

        CONSORT guidelines state that these terms should no longer be used because they are ambiguous. For instance, “double-blind” may mean that the data analysts and patients were blinded; the patients and outcome assessors were blinded; or the patients and those administering the intervention were blinded. The terms also fail to convey the information that was masked and the extent of unblinding. It is not sufficient to specify the number of parties that have been blinded. To describe an experiment’s blinding, it is necessary to report who has been blinded to what information, and how well each blind succeeded.

        So double blind doesn’t have to mean the researchers or even the participants were blinded, just that two parties were.

        In this specific study, I think it’s that the data analysts were not aware of which groups the data came from.

        • elephantium@lemmy.worldOPEnglish
          1·
          10 hours ago

          Huh, that doesn’t match my understanding (TBF I don’t work in the field).

          Looking again at the study… Dr. Jain had a second person split the students into two groups. I’m not sure whether she conducted the followup exams or had yet another person do that. Assuming that the students were strict about not talking about which toothbrush they were using, I suppose you could call it a ‘blinded’ experiment. I don’t really see how you could double it, though.