Second, it was recognized that rigorous, standardized anginal class assessment (e.g., the Seattle Angina Questionnaire), though standard in clinical trials, is not typically performed in the clinical setting, and that more common systems, like the Canadian Classi - cation System, have poor reliability and are too subjective. These issues created a tension between the feasibility of a measure related to angina assessment and its usefulness. For these reasons, the writing committee decided not to include an assessment of angina in the present set, but it believes this should be an area of future development. 6.2.2. Thirty-Day Mortality Rate The writing committee considered a mortality measure, and the 30-day endpoint was discussed in particular, because this was identi ed as the time point (as opposed to 1 year) at which outcomes would be most closely related to the index procedure. For the reasons discussed in Section 4.2, death as an outcome measure has obvious appeal. It is overall an unambiguous and unarguable endpoint and, along with stroke, is generally considered one of the worst possible outcomes of a PCI procedure. The challenges to using 30-day mortality rate as a performance measure relate pri- marily to risk-adjustment issues, and 2 main sentiments prevailed: 1) There was a strong desire to avoid penalizing operators for taking dif cult cases. This arose from recog- nition that risk adjustment is less robust at the extremes of risk, as well as from acknowledgment of some of the un- intended negative consequences that could result from focus on this outcome, at the individual-operator level, in terms of avoidance of dif cult cases altogether or an undesirable displacement of them to nearby regions and operators subject to lesser scrutiny. 