ISSN:0277-6715    

DOI:10.1002/sim.4780010102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractEffective statistical help to biological and medical research demands thorough involvement of the statistician. The breadth of his activities can be illustrated by considering the questions he needs to discuss with his scientific colleagues in the course of planning a comparative experiment. The paper presents and comments on 22 such questions, showing their relation to the objectives of the experiment, the utilization of resources, and the subsequent statistical analysis. A final paragraph urges that proper attention to all these points forms an integral part of an ethical approach to experimentation.

ISSN:0277-6715    

DOI:10.1002/sim.4780010103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe benefits and risks of screening for breast cancer, including both mammographic and clinical examinations, are analysed by means of a probabilistic model. The model, applied to previously unpublished data provided by the HIP (Health Insurance Plan of Greater New York) breast cancer screening project, permits more precise stratification by age than previous analyses and allows for incorporation of oncogenic risks due to mammography. It is assumed that, from the tenth year of screening onward, radiation induces 6 cases of breast cancer per year per million women screened per rad delivered to the breast tissue per exam.The predicted pattern of breast cancer cases and deaths is commensurate with that actually observed in the first nine years of the HIP study. In extrapolation to lifetime experience, the model predicts an ultimate decrease in the probability of dying of breast cancer only for women over age fifty at initial screening and an increase in life expectancy for the entire screened group, at an exposure level of three rads per exam. Had radiation dosage been one rad or less per exam, which is within the range now possible with modern equipment and procedures, the radiation risk would not offset even a modest benefit such as is predicted for the younger women, either in number of deaths or years of life expectancy.

ISSN:0277-6715    

DOI:10.1002/sim.4780010104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractSmall but important therapeutic effects of new treatments can be most efficiently detected through the study of large randomized prospective series of patients. Such large scale clinical trials are nowadays commonplace. The alternative is years of polemic and debate surrounding several trials each too small to detect plausible differences with any certainty. Such trials produce equivocal and contradictory results, which could be predicted from power calculations based upon sensible pre‐trial estimates of treatment differences. Unfortunately such calculations often lead to sample sizes of several thousands.It is not surprising that investigators tend to be over‐optimistic in their estimation of treatment effects (which are necessarily uncertain) especially when the sample size requirements are so stark. In this paper a method is outlined for incorporating into the sample size calculations the uncertainty of the estimate made at the design stage of a clinical trial. In particular a formal scheme is described for deciding how many interim analyses should be performed to satisfy ethical and pragmatic requirements of large clinical trial design. Although the argument will be ‘Bayesian’, the criteria for assessment and comparison will be strictly of a Neyman‐Pearson (i.e. significance test

ISSN:0277-6715    

DOI:10.1002/sim.4780010105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThis paper demonstrates that the Mantel‐Haenszel chi‐square statistic may be employed to test the equality of two directly standardized rates. For certain epidemiological applications, this eliminates the need for special computer programs to contrast two directly standardized rates. Furthermore, since the weights are determined entirely by the data there is the advantage of avoiding the selection of an external standard population. Data analysts who compare two groups of rates with the Mantel‐Haenszel chi‐square statistic may view this statistic as a comparative measure of two directly adjuste

ISSN:0277-6715    

DOI:10.1002/sim.4780010106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractWe empirically developed a logistic function to predict acute coronary heart disease (ACHD) and then tested it to determine its usefulness to emergency room physicians in diagnosis and admission of patients with suspected ACHD to the coronary care unit. The function was based on nine clinical, historical and electrocardiographic variables from a set of 105 variables collected on 643 patients with suspected ACHD. In the second phase of the study, we provide the probabilities generated by the function to emergency room physicians during alternate months as a supplement to existing diagnostic modalities. Use of the probability of ACHD (401 patients with probabilities versus 455 patients without probabilities) resulted in statistically significant improvement in diagnostic rates and reduction in the number of inappropriate admissions to the coronary care unit.

ISSN:0277-6715    

DOI:10.1002/sim.4780010107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractSeveral biomedical experiments have as their objective the determination of a relationship between a pair of time series. Often, the investigator wishes to discover if one series has a lagged dependence on the other. The analysis required in such an experiment involves a three step approach utilizing both multiple regression and time series techniques. This paper presents an example of this type of experiment and describes the steps to be followed in analysing the results.

ISSN:0277-6715    

DOI:10.1002/sim.4780010108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe general standard of statistics in medical journals is poor. This paper considers the reasons for this with illustrations of the types of error that are common. The consequences of incorrect statistics in published papers are discussed; these involve scientific and ethical issues. Suggestions are made about ways in which the standard of statistics may be improved. Particular emphasis is given to the necessity for medical journals to have proper statistical refereeing of submitted papers.

ISSN:0277-6715    

DOI:10.1002/sim.4780010109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe steps in designing a controlled trial to evaluate a new treatment for inoperable carcinoma of the bronchus are described. The principal outcome measure is survival time from treatment allocation, and the duration of the trial is determined by application of the sequential logrank test. The detailed determination of the stopping rule and the arrangements for analyses are described.

ISSN:0277-6715    

DOI:10.1002/sim.4780010110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractWe describe distribution‐free statistical methodology for assessing the equivalence of paired growth curves. This procedure may be used with incomplete observations, and in situations where parametric models for growth are inappropriate. We present data from an experiment investigating an immunotherapy regimen in a murine tumour system and which we have analysed with this techniqu

ISSN:0277-6715    

DOI:10.1002/sim.4780010111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY