Limitations include the use of proxy measures and some forms of selection bias, which may lead to underestimation of symptom levels.

Background: Use of serum creatinine to estimate GFR may lead to underestimation of the association between self-reported frailty and kidney function.

Stool culture remains the "gold standard" for cholera diagnosis; however, its lack of sensitivity may lead to underestimation of test specificity.

Donegal and Mayo were down, but poor census weather in May and June could have led to underestimation.

In this conceptual model, the assumptions of the proportional hazard model are violated, leading to underestimation of the importance of dialysis dosage.