Threshold methods are designed for the specific purposes of determining the strength or concentration of a stimulus required to produce: a minimal detectable effect (detection threshold), recognizable effect (recognition threshold), or change in effect (difference threshold). In any threshold method there can be two criteria for response: one is detection, in which the respondent has only to respond to differences from some product or background, and the other is recognition, in which the respondent must name the specific stimulus, for example, “salt” or “strong.”