Comparing the Predictive Powers of Survival Models Using Harrell's C or Somers’ D
نویسندگان
چکیده
منابع مشابه
Comparing the predictive power of survival models using Harrell’s c or Somers’ D
Medical researchers frequently make statements that one model predicts survival better than another, and are frequently challenged to provide rigorous statistical justification for these statements. Stata provides the command estat concordance to calculate the rank parameters Harrell’s c and Somers’ D as a measure of the ordinal predictive power of a model. However, no confidence limits or P–va...
متن کاملInterpretation of Somers’ D under four simple models
(where E[·] denotes expectation), or, equivalently, as the difference between the probability that the two X,Y –pairs are concordant and the probability that the two X,Y –pairs are discordant. A pair of X,Y –pairs is said to be concordant if the larger X–value is paired with the larger Y –value, and is said to be discordant if the larger X–value is paired with the smaller Y –value. Somers’ D of...
متن کاملassessment of the efficiency of s.p.g.c refineries using network dea
data envelopment analysis (dea) is a powerful tool for measuring relative efficiency of organizational units referred to as decision making units (dmus). in most cases dmus have network structures with internal linking activities. traditional dea models, however, consider dmus as black boxes with no regard to their linking activities and therefore do not provide decision makers with the reasons...
Comparing Powers and Symbolic Powers of Ideals
We develop tools to study the problem of containment of symbolic powers I(m) in powers I for a homogeneous ideal I in a polynomial ring k[P ] in N + 1 variables over an arbitrary algebraically closed field k. We obtain results on the structure of the set of pairs (r, m) such that I(m) ⊆ I. As corollaries, we show that I2 contains I(3) whenever S is a finite generic set of points in P2 (thereby ...
متن کاملthe use of appropriate madm model for ranking the vendors of mci equipments using fuzzy approach
abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a ...
15 صفحه اولذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: The Stata Journal: Promoting communications on statistics and Stata
سال: 2010
ISSN: 1536-867X,1536-8734
DOI: 10.1177/1536867x1001000303