Abstract:
:We examine the properties of several tests for goodness-of-fit for multinomial logistic regression. One test is based on a strategy of sorting the observations according to the complement of the estimated probability for the reference outcome category and then grouping the subjects into g equal-sized groups. A g x c contingency table, where c is the number of values of the outcome variable, is constructed. The test statistic, denoted as Cg, is obtained by calculating the Pearson chi2 statistic where the estimated expected frequencies are the sum of the model-based estimated logistic probabilities. Simulations compare the properties of Cg with those of the ungrouped Pearson chi2 test (X2) and its normalized test (z). The null distribution of Cg is well approximated by the chi2 distribution with (g-2) x (c-1) degrees of freedom. The sampling distribution of X2 is compared with a chi2 distribution with n x (c-1) degrees of freedom but shows erratic behavior. With a few exceptions, the sampling distribution of z adheres reasonably well to the standard normal distribution. Power simulations show that Cg has low power for a sample of 100 observations, but satisfactory power for a sample of 400. The tests are illustrated using data from a study of cytological criteria for the diagnosis of breast tumors.
journal_name
Stat Medjournal_title
Statistics in medicineauthors
Fagerland MW,Hosmer DW,Bofin AMdoi
10.1002/sim.3202subject
Has Abstractpub_date
2008-09-20 00:00:00pages
4238-53issue
21eissn
0277-6715issn
1097-0258journal_volume
27pub_type
杂志文章abstract::Propensity score analysis is widely used in observational studies to adjust for confounding and estimate the causal effect of a treatment on the outcome. When the outcome is survival time, there are special considerations on the definition of the causal estimand, point, and variance estimation that have not been thoro...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7839
更新日期:2018-11-20 00:00:00
abstract::Funnel plots are widely used to visualize grouped data, for example, in institutional comparison. This paper extends the concept to a multi-level setting, displaying one level at a time, adjusted for the other levels, as well as for covariates at all levels. These level-adjusted funnel plots are based on a Markov chai...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5677
更新日期:2014-09-20 00:00:00
abstract::We propose a new design for dose finding for cytotoxic agents in two ordered groups of patients. By ordered groups, we mean that prior to the study there is clinical information that would indicate that for a given dose one group would be more susceptible to toxicities than patients in the other group. The designs are...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7133
更新日期:2017-01-30 00:00:00
abstract::We describe the usual statistical concepts and consequent appropriate simulations of a prospective study for the simple case of a single risk variable and an assumed logistic model. We examine the simulations of Lilienfeld and Pyne, and show that they are seriously flawed. Contrary to those authors' claims, the estima...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780040212
更新日期:1985-04-01 00:00:00
abstract::Two features commonly exhibited by randomized trials of health promotion interventions are cluster randomization and stratification. Ignoring correlations between individuals within clusters can lead to an inflated type I error rate and hence a P-value which overstates the significance of the result. This paper compar...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1256
更新日期:2002-12-30 00:00:00
abstract::The lifetime risk of a clinical condition is the probability of onset of the condition during one's lifespan. Recent advances in Alzheimer's disease (AD) research have identified screening tests for biomarkers that can identify persons who are in the earliest stages of the AD process but who do not yet have any clinic...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8056
更新日期:2019-04-30 00:00:00
abstract::We present a new method of detection and inference for spatial clusters of a disease. To avoid ad hoc procedures to test for clustering, we have a clearly defined alternative hypothesis and our test statistic is based on the likelihood ratio. The proposed test can detect clusters of any size, located anywhere in the s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780140809
更新日期:1995-04-30 00:00:00
abstract::In multiple-record systems estimation it is usually assumed that all registration relate to the same population. In this paper, we develop a method which can be used when the registrations relate to different populations, in the sense that they cover, for example, different time periods or regions. We show that under ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1818
更新日期:2004-07-30 00:00:00
abstract::Cancer immunotherapy trials have two special features: a delayed treatment effect and a cure rate. Both features violate the proportional hazard model assumption and ignoring either one of the two features in an immunotherapy trial design will result in substantial loss of statistical power. To properly design immunot...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8440
更新日期:2020-03-15 00:00:00
abstract::The focus of this paper is dietary intervention trials. We explore the statistical issues involved when the response variable, intake of a food or nutrient, is based on self-report data that are subject to inherent measurement error. There has been little work on handling error in this context. A particular feature of...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.7011
更新日期:2016-11-10 00:00:00
abstract::In medical research, risk difference (RD) and number needed to treat (NNT) measures for survival times have been mainly proposed without consideration of covariates. In this paper, we develop adjusted RD and NNT measures for use in observational studies with survival time outcomes within the framework of the Cox propo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3793
更新日期:2010-03-30 00:00:00
abstract::This paper presents a procedure for obtaining short-term projections and lower bounds on the size of the acquired immunodeficiency syndrome (AIDS) epidemic. The method is similar to that proposed by Brookmeyer and Gail but adapted to the situation where individual dates of AIDS diagnosis are available. It gives result...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780081210
更新日期:1989-12-01 00:00:00
abstract::In noninferiority studies, a limit of indifference is used to express a tolerance in results such that the clinician would regard such results as being acceptable or 'not worse'. We applied this concept to a measure of accuracy, the Receiver Operating Characteristic (ROC) curve, for a sequence of tests. We expressed a...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.5741
更新日期:2013-07-20 00:00:00
abstract::In this paper we examine the efficiency of a generalization of the traditional normal linear (LDA) or quadratic (QDA) discriminant analysis. This procedure (the generalized discriminant analysis, GDA) replaces each normal density used in the traditional classification rule by a Fourier series density estimator which '...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780100319
更新日期:1991-03-01 00:00:00
abstract::The microbiome plays an important role in human health by mediating the path from environmental exposures to health outcomes. The relative abundances of the high-dimensional microbiome data have an unit-sum restriction, rendering standard statistical methods in the Euclidean space invalid. To address this problem, we ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8808
更新日期:2021-02-20 00:00:00
abstract::Although the frequentist paradigm has been the predominant approach to clinical trial design since the 1940s, it has several notable limitations. Advancements in computational algorithms and computer hardware have greatly enhanced the alternative Bayesian paradigm. Compared with its frequentist counterpart, the Bayesi...
journal_title:Statistics in medicine
pub_type: 杂志文章,评审
doi:10.1002/sim.5404
更新日期:2012-11-10 00:00:00
abstract::We consider a latent variable hazard model for clustered survival data where clusters are a random sample from an underlying population. We allow interactions between the random cluster effect and covariates. We use a maximum pseudo-likelihood estimator to estimate the mean hazard ratio parameters. We propose a bootst...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970915)16:17<2009::aid-s
更新日期:1997-09-15 00:00:00
abstract::We discuss the use of the trichotomous logistic model to discriminate between patients with gastrointestinal (GI) cancer, patients with benign GI disease and 'normal' subjects, using symptoms and the concentrations of some serum proteins that are potentially indicative of malignancy as covariates. A parsimonious model...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780040313
更新日期:1985-07-01 00:00:00
abstract::The proposed guidelines for the assessment of the effect of new pharmaceutical agents on the QT interval (beginning of QRS complex to end of T wave on the electrocardiogram) are based on the maximum of a series over time of simple one-sided 95 per cent upper confidence bounds. This procedure is typically very conserva...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2826
更新日期:2007-09-10 00:00:00
abstract::Among subjects who have experienced a biological event, such as menarche, menopause or a delivery, one cannot distinguish the effects of time since the event from age at the event due to the linear dependency among these time variables and age at study ('current age'). This is a well-known problem that also exists in ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(SICI)1097-0258(19960730)15:14<1545::AID-S
更新日期:1996-07-30 00:00:00
abstract::While genome-wide association studies (GWASs) have been widely used to uncover associations between diseases and genetic variants, standard SNP-level GWASs often lack the power to identify SNPs that individually have a moderate effect size but jointly contribute to the disease. To overcome this problem, pathway-based ...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8442
更新日期:2020-03-15 00:00:00
abstract::Suppose that two graders classify all eyes in a sample of patients for the presence or absence of a specified abnormality. In the statistical analysis of the data, possible correlation between the observations in the right and left eyes should be taken into account. Recently, general methods have been developed to ana...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4780122306
更新日期:1993-12-15 00:00:00
abstract::Tree-based methods have become popular for analyzing complex data structures where the primary goal is risk stratification of patients. Ensemble techniques improve the accuracy in prediction and address the instability in a single tree by growing an ensemble of trees and aggregating. However, in the process, individua...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.4492
更新日期:2012-07-10 00:00:00
abstract::The purpose of this paper is to show that the sensitivity and specificity estimates obtained by 'discrepant analysis' are biased. Discrepant analysis is a widely used technique that attempts to provide estimates of sensitivity and specificity in the presence of an imperfect gold standard. Many researchers have applied...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1097-0258(19970630)16:12<1391::aid-s
更新日期:1997-06-30 00:00:00
abstract::We study prevalence-dependent diagnostic accuracy measures, specifically, positive and negative predictive values. These measures permit an assessment of the clinical utility of diagnostic tests across populations with different disease prevalences. In many cases, prevalence may not be known with certainty and the eva...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.2812
更新日期:2007-07-30 00:00:00
abstract::The log-rank test is the most powerful non-parametric test for detecting a proportional hazards alternative and thus is the most commonly used testing procedure for comparing time-to-event distributions between different treatments in clinical trials. When the log-rank test is used for the primary data analysis, the s...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.3501
更新日期:2009-02-28 00:00:00
abstract::We suggest measures to quantify the degrees of necessity and of sufficiency of prognostic factors for dichotomous and for survival outcomes. A cause, represented by certain values of prognostic factors, is considered necessary for an event if, without the cause, the event cannot develop. It is considered sufficient fo...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.8331
更新日期:2019-10-15 00:00:00
abstract::The U.S. Food and Drug Administration (FDA) has proposed new regulations that address the 'prescribability' and 'switchability' of new formulations of already-approved drugs. These new criteria are known, respectively, as population and individual bioequivalence. Two methods have been proposed in the bioequivalence li...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.1346
更新日期:2003-01-15 00:00:00
abstract::When estimating the probability of natural conception from observational data on couples with an unfulfilled child wish, the start of assisted reproductive therapy (ART) is a competing event that cannot be assumed to be independent of natural conception. In clinical practice, interest lies in the probability of natura...
journal_title:Statistics in medicine
pub_type: 杂志文章
doi:10.1002/sim.6280
更新日期:2014-11-20 00:00:00
abstract::We have formulated the problem of determining whether there has been an upturn in HIV-1 seroconversion incidence over the first five years of follow-up in the Multicenter AIDS Cohort Study (MACS) as that of locating the minimum of a quadratic regression or examination of two-knot piecewise spline models. Under a quadr...
journal_title:Statistics in medicine
pub_type: 杂志文章,多中心研究
doi:10.1002/sim.4780120207
更新日期:1993-01-30 00:00:00