VIRUSMYTH HOMEPAGE
SURVEYING ASCHER AND SCHECHTER
By John Lauritsen
Rethinking AIDS May 1993
Two reports have recently appeared that claim to refute Peter Duesberg's
risk-AlDS hypothesis on the basis of cohort studies. One, by M.S. Ascher
et al., rebukes Duesberg in the final paragraph: "The energies of
Duesberg and his followers could better be applied to unraveling the enigmatic
mechanism of the HIV pathogenesis of AIDS" (M.S. Ascher et al., "Does
drug use cause AIDS?", Nature, 11 March 1993).
The other, by Martin T. Schechter et al., also rebukes Duesberg in the
final paragraph: "It is a disservice to the many people infected with
HIV-1 and a hindrance to public health initiatives for scientists to claim
that HIV-1 is harmless and not aetiologically related to AIDS" (Martin
T. Schechter et al., "HIV-1 and the aetiology of AIDS," Lancet,
13 March 1993).
Both studies are forms of survey research, my profession since 1966.
In a letter to me (14 April 1993), Martin Schechter denies this, which
merely indicates his ignorance of basic concepts. In survey research, data
from a selected sample are projected to represent a greater universe or
population. As explained in one of the classic texts of my field:
"Sampling, as probably everyone knows, arises from the impossibility
or impracticability of studying an entire population. It is not very feasible,
if at all possible, to study the entire population of the United States
at a given time, nor is it necessary to test the entire contents of a well-sifted
grain barrel to determine its quality content. Even where it is advisable
to study an entire population, time and cost elements are usually prohibitive.
Essentially. sampling is a problem in inference, the aim being to
secure sufficient information from a representative segment of the population
to enable one to infer the true state of affairs with respect to
the characteristics under observation for the entire population within
a certain range of error." (Robert Ferb, Statistical Techniques
in Market Research, New York, 1949)
Both studies claim to support the HIV-AIDS hypothesis. Both studies
are highly implausible, if for no other reason, because they show that
drugs don't do anything. But drugs are not sugar pills, and there are physical
consequences to putting them in human bodies.
After reading the two brief reports, I had grave doubts that the researchers
understood how to design, conduct, or analyze survey research. I wrote
to Ascher and Schechter, asking permission to look at raw data, questionnaires,
and other study materials. Ascher did not reply. Schechter wrote:
"Unfortunately, your request to inspect our raw data and other
documents is problematic. As you are no doubt aware, there are tremendous
concerns surrounding confidentiality in studies of this type. In our informed
consent, we have specifically promised not only all the participants but
their practitioners that the data we collect will not be seen by any individuals
or agencies outside the investigators involved in the study. To allow anyone
else to inspect the raw data would constitute a breach of this fundamental
promise."
Schechter ignored the most specific request I made in my letter: a copy
of the self-administered questionnaire he mentioned in his article. I fail
to see how the release of a blank questionnaire or of data, consisting
of grouped numbers, could violate promises of confidentiality. Apparently
Schechter expects us to accept his research on faith.
One of the cardinal principles of science is openness, which
means sharing data and describing methodology in sufficient detail that
a study could be replicated or in some other way verified. Although
replication might not be possible or practical, there is another way the
worth of the data could be evaluated through validation.
In professional survey research, it is the practice to validate all
studies, using sophisticated techniques. Let's suppose that an in-person
survey was conducted by local interviewers in a dozen cities around the
country. After the questionnaires have come back from the field, interviewers
from the home office, using WATS lines, validate a percentage of each interviewer's
work. This means calling respondents and asking a few questions designed
to ascertain that the rules of the study were followed. If even a single
questionnaire fails the validation test, then validation is performed upon
100% of that interviewer's work. In the extremely rare event that cheating
is discovered, the culprits are severely punished.
An unvalidated survey has little or no credibility. Since neither the
Ascher nor the Schechter study is even open to validation, they deserve
to be rejected on this basis alone. In addition, neither author describes
the characteristics of the samples, so one has no idea how representative
they might be of the populations from which they were allegedly drawn.
It has been my experience as an analyst, without exception, that when
data don't make sense it is because there is something wrong with them.
It doesn't make sense that a single, biochemically inactive microbe could
be the cause of the 29 (at last count) AIDS-indicator diseases. And it
doesn't make sense that drugs don't do anything.*
VIRUSMYTH HOMEPAGE