scholarly journals The True Coefficient of Mortality

Nature ◽  
1881 ◽  
Vol 24 (616) ◽  
pp. 357-357
Author(s):  
JOHN LE CONTE
Keyword(s):  
True Coefficient

Influence of Variability of Interpretation of Contrast Venography for Screening of Postoperative Deep Venous Thrombosis on the Results of a Thromboprophylactic Study

1993 ◽  
Vol 70 (04) ◽  
pp. 573-575 ◽  
Author(s):  
Frédéric Couson ◽  
Colette Bounameaux ◽  
Cominique Didier ◽  
Daniel Geiser ◽  
Michael F Meyerovitz ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Low Molecular Weight Heparin ◽  
Interobserver Variability ◽  
Initial Evaluation ◽  
Lower Limbs ◽  
Low Molecular Weight ◽  
True Coefficient ◽  
Heparin Fractions ◽  
Postoperative Deep Venous Thrombosis

SummaryTo assess interobserver variability of venography for screening for postoperative deep venous thrombosis (DVT), we used 185 bilateral ascending contrast venograms (366 lower limbs) which were performed using the long-leg film technique, in the frame of a trial of the efficacy of two low-molecular-weight-heparin fractions (initial evaluation). These venograms were submitted in a multicenter setting to three further readers who performed a serial scoring as DVT, no DVT or non-evaluable. DVTs were diagnosed in 78, 55 and 59/366 limbs (initial evaluation: 58). The proximal locations of DVTs were 16, 9 and 16 (initial evaluation: 15) and the non evaluable limbs 3, 5 and 18 (initial evaluation: 0). Apparent pairwise agreement between the three readers ranged from 87 to 90% (true coefficient of agreement Kappa 0.63-0.70). It ranged from 89 to 93% (Kappa 0.63-0.74) for the comparison between the readers and the initial evaluation. This considerable degree of disagreement among experienced readers should be taken into account in calculating sample sizes in prospective thromboprophylactic studies. Indeed, one of the two prophylactic regimens proved to be significantly (p = 0.012, p = 0.031, p = 0.049) or non-significantly (p = 0.073) superior to the other one depending upon the reading of venograms.

Equity Estimation and Assessing Market Response

1993 ◽  
Vol 30 (4) ◽  
pp. 437-451 ◽  
Author(s):  
Albert R. Wildt
Keyword(s):  
Least Squares ◽  
Explanatory Power ◽  
Predictor Variable ◽  
Ordinary Least Squares ◽  
Predictor Variables ◽  
Market Response ◽  
Response Functions ◽  
Coefficient Estimates ◽  
Simulation Experiments ◽  
True Coefficient

Equity estimation has been proposed as a possibly superior technique for estimating market response functions in the presence of high predictor-variable collinearity. The relative performance of equity, ridge, and ordinary least squares (OLS) estimators is examined using simulation experiments. In part, findings are consistent with prior research and indicate that, under certain conditions, equity outperforms OLS and ridge on a number of important criteria, and equity yields coefficient estimates that assign more equal explanatory weight to correlated predictor variables than does OLS or ridge. As collinearity increases, this tendency becomes very pronounced, to the point where equity yields estimated standardized coefficients more equal in magnitude irrespective of other conditions, such as true coefficient values and model explanatory power.

What is the true coefficient of partial correlation?

1972 ◽  
Vol 1 (2) ◽  
pp. 231-235 ◽  
Author(s):  
Samuel A Livingston ◽  
Julian C Stanley
Keyword(s):  
Partial Correlation ◽  
True Coefficient
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