Identifying constructs and criteria for the diagnosis of premature ejaculation: implication for making errors of classification.

OBJECTIVES: To review the many definitions of premature ejaculation (PE), determine the essential elements that best define PE, and examine and discuss the consequences of errors of inclusion and exclusion in the diagnosis of PE.
METHODS: We reviewed recent evidenced-based studies that delineate the variables that best define PE, and the relationships between these factors. We then assessed the consequences of errors of measurement, inclusion and exclusion for setting the thresholds for the three variables.
RESULTS: PE can best be defined by a multidimensional set of criteria composed of three essential elements: (i) intravaginal ejaculatory latency time (IELT); (ii) a lack of perceived self-efficacy or control about the timing of ejaculation; and (iii) distress and interpersonal difficulty related to the ejaculatory dysfunction. After delineating the variables, thresholds for each variable need to be determined. Carefully constructed thresholds attempt to minimize errors of inclusion and exclusion. However, even the best criteria cannot eliminate all error. The two types of errors in classification are, to some extent, inversely related: the more restrictive the criteria, the more likely that there will be errors of exclusion, whereas the more lenient the criteria the more likely there will be errors of inclusion.
CONCLUSION: Research and treatment protocols might use different threshold values for classification, as their goals might be different. For a PE research protocol, we suggest erring on the side of a more narrow definition as it would: (i) provide a more conservative, and we think, realistic prevalence of the disorder; (ii) help to establish PE as a bona fide sexual dysfunction rather than a 'life-style' issue for men seeking to enhance their sexual life; (iii) ensure greater confidence in the efficacy of existing and new treatment approaches; and (iv) strengthen the likelihood of acceptance by the regulatory authorities. Conversely, standard treatment protocols for PE might use more lenient criteria if the treatment has minimal adverse events and the degree of distress of the sufferer is high.