[teejers1]

Ahem -- for those who were skeptical of my acting in bad faith accusation:

[tweet]https://twitter.com/CT_Bergstrom/status/1253752435467710464?s=20[/tweet]

A Stanford University professor’s wife invited parents in a wealthy enclave of Northern California to sign up for her husband’s coronavirus antibody study this month, falsely claiming that an “FDA approved” test would tell them if they had immunity and could “return to work without fear,” according to an email obtained by BuzzFeed News.

The email, sent to a listserv for Ardis G. Egan Junior High School in the city of Los Altos on Friday, April 2, advertised a study set to begin that weekend. With the subject line “COVID-19 antibody testing - FREE,” the email described how participants could gain “peace of mind” and “know if you are immune.” The results would help researchers calculate the virus’s spread throughout the surrounding county of Santa Clara, according to the message sent by Catherine Su, a radiation oncologist married to Jay Bhattacharya, the Stanford professor of medicine leading the study.

Weeks later, early results from Bhattacharya’s team would conclude that, based on the tests, the area had 50 to 85 times more infections than reported cases. That finding, along with their claim that the coronavirus would therefore have a lower fatality rate than previously thought, made national headlines. But almost as immediately, the study came under fire from scientists, who said it was based on a heavily flawed data analysis that ignored questions about the antibody test’s false positive rate — as well as a problematic Facebook recruitment strategy.

The email reveals that the researchers did not disclose another way participants were recruited that could have further skewed the results. In addition to targeting a specific demographic of parents in a wealthy part of Silicon Valley — making it even less likely that the participants represented a random sample — the email falsely claimed that the study’s antibody test was FDA approved, and was worded in a way that might have disproportionately attracted people who had previously been sick. It also misrepresented what participants could learn about their health from the testing.

Bhattacharya’s explanation is that he didn't know about the email and didn't approve it. Sure, so she invented all of this out of thin air with no knowledge or guidance from her husband? How did she even have enough knowledge about the study to be able to do this kind of promotion? And as an MD wife of a professor of medicine, surely she knows that making false claims about FDA approval and using unapproved means of solicitation for the study could compromise its integrity. Sure smells fishy to me.

I'm certainly not as learned as the many folks here who edify us with their lengthy posts on all things Covid-research, study, etc, reflecting such learnedness.  
So pardon the (undoubted) ignorance of my question.

I get why the population being tested should be "representative," to the extent possible.  What I don't get is why the motive for having the test would necessarily adversely affect the representative nature of the test.  In other words, let's say the advertising was:  "come get an antibody test; if you're found to have it, you're immune and can go back to work."  

How does that necessarily affect the representative nature of those being tested?

And since you can't force people to participate in a study, how can you guarantee "representativeness" of the participants?  Is it all about having them answer a questionnaire (where you assume answers are truthful) and then trying to take group having representative characteristics which the questions are trying to identify?

[teejers1]

Ahem -- for those who were skeptical of my acting in bad faith accusation:

[tweet]https://twitter.com/CT_Bergstrom/status/1253752435467710464?s=20[/tweet]

A Stanford University professor’s wife invited parents in a wealthy enclave of Northern California to sign up for her husband’s coronavirus antibody study this month, falsely claiming that an “FDA approved” test would tell them if they had immunity and could “return to work without fear,” according to an email obtained by BuzzFeed News.

The email, sent to a listserv for Ardis G. Egan Junior High School in the city of Los Altos on Friday, April 2, advertised a study set to begin that weekend. With the subject line “COVID-19 antibody testing - FREE,” the email described how participants could gain “peace of mind” and “know if you are immune.” The results would help researchers calculate the virus’s spread throughout the surrounding county of Santa Clara, according to the message sent by Catherine Su, a radiation oncologist married to Jay Bhattacharya, the Stanford professor of medicine leading the study.

Weeks later, early results from Bhattacharya’s team would conclude that, based on the tests, the area had 50 to 85 times more infections than reported cases. That finding, along with their claim that the coronavirus would therefore have a lower fatality rate than previously thought, made national headlines. But almost as immediately, the study came under fire from scientists, who said it was based on a heavily flawed data analysis that ignored questions about the antibody test’s false positive rate — as well as a problematic Facebook recruitment strategy.

The email reveals that the researchers did not disclose another way participants were recruited that could have further skewed the results. In addition to targeting a specific demographic of parents in a wealthy part of Silicon Valley — making it even less likely that the participants represented a random sample — the email falsely claimed that the study’s antibody test was FDA approved, and was worded in a way that might have disproportionately attracted people who had previously been sick. It also misrepresented what participants could learn about their health from the testing.

Bhattacharya’s explanation is that he didn't know about the email and didn't approve it. Sure, so she invented all of this out of thin air with no knowledge or guidance from her husband? How did she even have enough knowledge about the study to be able to do this kind of promotion? And as an MD wife of a professor of medicine, surely she knows that making false claims about FDA approval and using unapproved means of solicitation for the study could compromise its integrity. Sure smells fishy to me.

I'm certainly not as learned as the many folks here who edify us with their lengthy posts on all things Covid-research, study, etc, reflecting such learnedness.  
So pardon the (undoubted) ignorance of my question.

I get why the population being tested should be "representative," to the extent possible.  What I don't get is why the motive for having the test would necessarily adversely affect the representative nature of the test.  In other words, let's say the advertising was:  "come get an antibody test; if you're found to have it, you're immune and can go back to work."  

How does that necessarily affect the representative nature of those being tested?

And since you can't force people to participate in a study, how can you guarantee "representativeness" of the participants?  Is it all about having them answer a questionnaire (where you assume answers are truthful) and then trying to take group having representative characteristics which the questions are trying to identify?