Maximum likelihood estimation is a method commonly used for parameter estimation. The main disadvantage of this method is that it can be heavily biased for small samples. Firth (Biometrika,1993) suggested method for reduction in bias through a penalization of the likelihood. This bias reduction method is used frequently. LogXact®, SAS® and STATA® provided this method for binary regression. In c...

A new regression-based method of assessing test bias is proposed. We highlight two different potential causes of differences in groups' regression line intercepts. Intercepts differing due to mean criterion score differences are not interpreted as predictive test bias. Using both simulated and employee data, we illustrate this new approach. Test bias is a systematic error in how a test measures...

purpose: to compare the tono-pen and schiotz tonometers in measurement of intraocular pressure (iop) in patients with primary congenital glaucoma. methods: this study was conducted on 38 eyes of 20 patients with primary congenital glaucoma. all measurements were performed under general anesthesia. one minute after receiving halothane 3% iop was determined by tono-pen and then by schiotz tonomet...

CONTEXT Egger's regression test is often used to help detect publication bias in meta-analyses. However, the performance of this test and the usual funnel plot have been challenged particularly when the summary estimate is the natural log of the odds ratio (lnOR). OBJECTIVE To compare the performance of Egger's regression test with a regression test based on sample size (a modification of Mac...

Although the European Respiratory Society (ERS) proposes using percentiles or standardized residuals for reporting results of lung volume measurements [1], this approach has not been widely accepted, and percentages are still being used, mainly because calculations and interpretation are easier to perform. Our group has reported that both for spirometry [2] and total lung capacity (TLC) measure...

The empirical semivariogram of residuals from a regression model with stationary errors may be used to estimate the covariance structure of the underlying process. For prediction (kriging) the bias of the semivariogram estimate induced by using residuals instead of errors has only a minor eeect because the bias is small for small lags. However, for estimating the variance of estimated regressio...

The estimate of the frequency of suppressor T lymphocytes in unfractionated cell populations remains challenging, mainly because these regulatory cells do not display specific immunophenotypic markers. In this paper, we describe a novel theoretical approach for quantifying the frequency of suppressor cells. This method is based on limiting dilution data modeling, and allows the simultaneous est...