The concept of linear<unk> , thresholds, and all-or-nothing responses may not apply to non-linear situations. A threshold model or linear no-threshold model may be more appropriate, depending on the circumstances. A recent critique of these models as they apply to endocrine disruptors argues for a substantial revision of testing and toxicological models at low<unk> s because of observed non-monotonicity, i.e. U-shaped<unk> /response curves.<unk> s generally depend on the exposure time and exposure route (e.g., inhalation, dietary intake); quantifying the response after a different exposure time or for a different route leads to a different<unk>  and possibly different conclusions on the effects of the stressor under consideration. This limitation is caused by the complexity of biological systems and the often unknown biological processes operating between the external exposure and the adverse cellular or tissue response.
Dose–response relationship
Weekend effect
Proportional reporting ratio
N of 1 trial
Phase response curve
Positive-incentive value
Widowhood effect
Surrogate endpoint