The laboratory Leghorn line was somewhat inbred, and may also under-represent the SNP polymorphisms within the commercial Leghorn lines.
They may also under-procure drugs to cause a shortage which is then covered by the private market.
Post hospitalisation surveys may also under-represent males and older patients unless these groups are targeted by more vigorous follow-up methods [ 77].
Finally, incomplete follow-up, besides potentially missing some neonates with hearing loss, may also under- or over-estimate programme performance by affecting the age at diagnosis, prevalence, percentage of newborns eligible for definitive audiological evaluation, and false positive rate.
The formation may also be under-pressurized, further complicating the drilling process.
Girls with cancer may also be under-diagnosed compared with boys.
Because cultural, legal, or personal considerations may affect reporting, serious adverse events may also be under-reported.
Late onset disease incidence estimates based upon community population denominators (Dominican Republic) may also have under-estimated incidence.
Parents may also have under-reported what they felt was more acceptable e.g. fewer hours of television watching.
