"Researchers in Japan tested the effect of cannabidiol (CBD) i...

Question

"Researchers in Japan tested the effect of cannabidiol (CBD) in treating late teenagers with social anxiety disorder (SAD). Thirty-seven 18- to 19-year-old teenagers with SAD took part in the study. The patients were assigned at random to receive a daily dose of either CBD or a placebo for 4 weeks. Symptoms were measured using The Fear of Negative Evaluation Questionnaire and the Liebowitz Social Anxiety Scale at the beginning and end of the treatment. (Source: Frontiers in Psychology)
Identify a potential problem with the experimental design being used and suggest a way to improve it."

Identify a potential problem with the experimental design being used and suggest a way to improve it."

Accepted Answer

Hi, everyone. Let's look at our next question together. It says, A research team is evaluating the effectiveness of a new breathing technique for reducing anxiety in young adults. A total of 36 participants aged 18 to 19, all diagnosed with mild anxiety, volunteer for the study. They are randomly assigned to practice either the breathing technique or a control activity, sitting quietly each day for 4 weeks. Anxiety levels are measured using two standard psychological scales at the beginning and the end of the study. Identify one potential problem in this experimental design and suggest a way to improve it. Well, we can see that this is a pretty well designed experiment. We have random assignment of the participants to a control group or test group. We have a control activity, so not just breathing technique or nothing. We have something that might also improve anxiety, but it's a different technique. And to measure our results, we have two different scales, and they're standard psychological scales, and we're measuring at the beginning and end. So you're not just asking people, do you think you're less anxious? You have these standard uh well accepted scales, where you're assessing beginning and ending level. So, at first we look at this and say, OK, this seems pretty well designed, but we're specifically told we should identify a potential problem. So, we have two potential problems here that we could discuss. We are discussing young adults, so we'd say, oh, there we go, young adults, 18 to 19, but young adult is a much wider age span. So, we'd say that a potential problem could be. That the age range of this sample is too narrow. Maybe we need participants aged 18 to 29 or something like that. So that's one area of criticism. And then another potential area of criticism. Not that it says what else it says about the participants. They're all diagnosed with mild anxiety. So having everybody with the same degree of anxiety. Sort of limits how much we can say about how effective this technique is for different levels of anxiety. So we'd say um should have participants. With different degrees of anxiety, you might not see the same results if you assessed people with more severe anxiety. So both of these problems are something that might uh affect the generalizability. Or we might say external validity of the study. So you want to make sure your sample is representative of the group that you're studying. So if we're studying young adults with anxiety, we'd want more than just 18 and 9 year olds, and we'd probably want different degrees of severity of that anxiety. So once again, we're talking about the study design, and you're supposed to look for one potential problem and suggest a way to improve it. And our two potential problems you could have picked either of them, is a narrow age range of the sample. So, obviously, um you could improve this, we'll specifically put that by. Have wider age range. And another potential problem would be that you should have participants with different degrees of anxiety, so including people with some more severe anxiety. So, that is our way that we might suggest to improve these two potential weaknesses of this particular study. See you in the next video.

Key Concepts

Randomization

Placebo Effect

Measurement Validity

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