Do you have a take on how accurate the national average estimates are? In particular, I’d be interested in whether they were determined using a different methodology, and so perhaps one that will be biased toward “underreporting”. Where as at first glance your methodology might seem to be biased toward “overreporting” (though idk to what extent you may have “corrected” for non-reponse bias, which would be one source of “overreporting”).
The national averages were determined using the same measurement instruments we used, but they did not control for non-respondents the way we did. My intuition is that the national averages are pretty accurate because they had big sample sizes and did not seem to be obviously sampling from a more depressed/anxious segment of the population.
But you can decide for yourself:
In a national sample collected by the National Health and Nutrition Examination Survey (n = 31,366), 8.75% of people in the United States meet the criteria for moderate to severe depression. When restricting the national sample to only those with a college degree or above (n = 6,660), national rates of moderate or severe depression were much lower than what we found in our graduate student sample: 3.8%
In a national sample (n = 5,030), 5.1% of Americans met the criteria for moderate or severe anxiety on the same measure (Löwe et al., 2008).
We controlled for non-responders by keeping track of how many reminders it took subjects to respond to the survey, and checked to see whether the harder it was to get people to respond predicted their depression or anxiety scores. It did not. We also had such a high response rate (30%) that even if all of our non-respondents felt depression or anxiety at rates equal to national averages (unlikely), the graduate students would still be worse off on average.
Interesting, thank you for sharing.
Do you have a take on how accurate the national average estimates are? In particular, I’d be interested in whether they were determined using a different methodology, and so perhaps one that will be biased toward “underreporting”. Where as at first glance your methodology might seem to be biased toward “overreporting” (though idk to what extent you may have “corrected” for non-reponse bias, which would be one source of “overreporting”).
The national averages were determined using the same measurement instruments we used, but they did not control for non-respondents the way we did. My intuition is that the national averages are pretty accurate because they had big sample sizes and did not seem to be obviously sampling from a more depressed/anxious segment of the population.
But you can decide for yourself:
In a national sample collected by the National Health and Nutrition Examination Survey (n = 31,366), 8.75% of people in the United States meet the criteria for moderate to severe depression. When restricting the national sample to only those with a college degree or above (n = 6,660), national rates of moderate or severe depression were much lower than what we found in our graduate student sample: 3.8%
In a national sample (n = 5,030), 5.1% of Americans met the criteria for moderate or severe anxiety on the same measure (Löwe et al., 2008).
We controlled for non-responders by keeping track of how many reminders it took subjects to respond to the survey, and checked to see whether the harder it was to get people to respond predicted their depression or anxiety scores. It did not. We also had such a high response rate (30%) that even if all of our non-respondents felt depression or anxiety at rates equal to national averages (unlikely), the graduate students would still be worse off on average.