Comment author:Flodorner
11 June 2018 07:49:32AM
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0 points
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The claim does not seem to be exactly, that there is a 10% chance of an animal advocacy video affecting consumption decisions after 12 years for a given individual.

I'd interpret it as: there is a 5% chance of the mean duration of reduction, conditioned on the participant reporting to change their behaviour based on the video being higher than 12 years.

This could for example also be achieved by having a very long term impact on very few participants. This interpretation seems a lot more plausible, although i am not certain at all, wheter that claim correct. Long term follow up data would certainly be very helpful.

Comment author:Halstead
11 June 2018 08:01:08AM
1 point
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Yes I was speaking somewhat loosely. It is nevertheless in my view very implausible that the intervention would sustain its effect for that long - we're talking about the effect of one video here. Do you think the chance of fade-out within a year is less than 10%? What is your median estimate?

Comment author:Flodorner
11 June 2018 08:55:19AM
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Are you talking about the individual level, or the mean? My estimate would be, that for the median individual, the effect will have faded out after at most 6 months. However, the mean might be influenced by the tails quite strongly.

Thinking about it for a bit longer, a mean effect of 12 years does seem quite implausible, though. In the limiting case, where only the tails matter, this would be equivalent to convincing around 25% of the initially influenced students to stop eating pork for the rest of their lives.

The upper bound for my 90% confidence interval for the mean seems to be around 3 years, while the lower bound is at 3 months. The probability mass within the interval is mostly centered to the left.

## Comments (18)

Best*0 points [-]The claim does not seem to be exactly, that there is a 10% chance of an animal advocacy video affecting consumption decisions after 12 years for a given individual.

I'd interpret it as: there is a 5% chance of the mean duration of reduction, conditioned on the participant reporting to change their behaviour based on the video being higher than 12 years.

This could for example also be achieved by having a very long term impact on very few participants. This interpretation seems a lot more plausible, although i am not certain at all, wheter that claim correct. Long term follow up data would certainly be very helpful.

Yes I was speaking somewhat loosely. It is nevertheless in my view very implausible that the intervention would sustain its effect for that long - we're talking about the effect of one video here. Do you think the chance of fade-out within a year is less than 10%? What is your median estimate?

Are you talking about the individual level, or the mean? My estimate would be, that for the median individual, the effect will have faded out after at most 6 months. However, the mean might be influenced by the tails quite strongly.

Thinking about it for a bit longer, a mean effect of 12 years does seem quite implausible, though. In the limiting case, where only the tails matter, this would be equivalent to convincing around 25% of the initially influenced students to stop eating pork for the rest of their lives.

The upper bound for my 90% confidence interval for the mean seems to be around 3 years, while the lower bound is at 3 months. The probability mass within the interval is mostly centered to the left.