Biomedical subjects

H B Kushner

Publications and source records attributed to H B Kushner.

3 recordsLinked to original sources

PubMed1996

Estimating population size when duplicates are present.

Each of K mental health programmes reports the number of patients served in a year. The sum of these numbers, y, is an overcount because some patients are seen in more than one programme. Health care planners need to know the unduplicated number served by the mental health system. Thus, there is an unknown number, M, of distinct individuals who appear on one or more of K lists; some appear on multiple lists and the duplicates are not readily identifiable. Let X be the number of lists on which a randomly selected individual appears. When E(X) is known, y/E(X) is the natural estimator of M. We assume that we know the number of programmes, Xi, used by the ith individual in a random sample of recipients of service. Here, the intuitive estimator, Y/X has desirable statistical properties. We give confidence interval estimators for M. We apply the method to estimate the number of individuals served in 1991 by the mental health programmes in New York State.

Confidence Intervals↗

PubMed1986

Combining multivariate bioassays.

Linear multivariate theory is applied to the problem of combining several multivariate bioassays. Results are an asymptotic test of the hypothesis of a common log relative potency; the maximum likelihood estimator of the common log relative potency; and an exact and asymptotic confidence interval estimator for log relative potency.

Analysis of Variance↗

PubMed1983

Optimal crossover designs in the presence of carryover effects.

Under either the random patient-effect model with sequence effects or the fixed patient-effect model, the usual two-period, two-treatment crossover design, AB,BA, cannot be used to estimate the contrast between direct treatment effects when unequal carryover effects are present. If baseline observations are available, the design AB,BA can validly be used to estimate a treatment contrast. However, the design AB,BA,AA,BB with baseline observations is more efficient. In fact, we show that this design is optimal whether or not baseline observations are available. For experiments with more than two periods, universally optimal designs are found for both models, with and without carryover effects. It is shown that uncertainty about the presence of carryover effects is of little or no consequence, and the addition of baseline observations is of little or no added value for designs with three or more periods; however, if the experiment is limited to only two periods the investigator pays a heavy penalty.

Clinical Trials as Topic↗