A Nonstochastic Interpretation of Reported Significance Levels

Tests of significance are often made in situations where the standard assumptions underlying the probability calculations do not hold. As a result, the reported significance levels become difficult to interpret. This article sketches an alternative interpretation of a reported significance level, valid in considerable generality. This level locates the given data set within the spectrum of other data sets derived from the given one by an appropriate class of transformations. If the null hypothesis being tested holds, the derived data sets should be equivalent to the original one. Thus, a small reported significance level indicates an unusual data set. This development parallels that of randomization tests, but there is a crucial technical difference: our approach involves permuting observed residuals; the classical randomization approach involves permuting unobservable, or perhaps nonexistent, stochastic disturbance terms.     

A Case Study in Nonresponse: Plaintiff vs. California State Board of Equalization

In any sample survey, nonresponse bias is a potential issue. Even with a moderately high nonresponse rate, however, covariates can sometimes be used to show that the nonresponse bias is likely to be small. This note presents such an argument, which was used by the winning side in a tax case.     

Methods to assess measurement error in questionnaires of sedentary behavior

Sedentary behavior has already been associated with mortality, cardiovascular disease, and cancer. Questionnaires are an affordable tool for measuring sedentary behavior in large epidemiological studies. Here, we introduce and evaluate two statistical methods for quantifying measurement error in questionnaires. Accurate estimates are needed for assessing questionnaire quality. The two methods would be applied to validation studies that measure a sedentary behavior by both questionnaire and accelerometer on multiple days. The first method fits a reduced model by assuming the accelerometer is without error, while the second method fits a more complete model that allows both measures to have error. Because accelerometers tend to be highly accurate, we show that ignoring the accelerometer's measurement error, can result in more accurate estimates of measurement error in some scenarios. In this article, we derive asymptotic approximations for the mean-squared error of the estimated parameters from both methods, evaluate their dependence on study design and behavior characteristics, and offer an R package so investigators can make an informed choice between the two methods. We demonstrate the difference between the two methods in a recent validation study comparing previous day recalls to an accelerometer-based ActivPal.     

ADHD and Brain Anatomy: What Do Academic Textbooks Used in the Netherlands Tell Students?

Studies of brain size of children classified with ADHD appear to reveal smaller brains when compared to ‘normal’ children. Yet, what does this mean? Even with the use of rigorously screened case and control groups, these studies show only small, average group differences between children with and without an ADHD classification. However, academic textbooks used in the Netherlands often portray individual children with an ADHD classification as having a different, malfunctioning brain that necessitates medical intervention. This conceptualisation of ADHD might serve professional interests, but not necessarily the interests of children.     

Pollution disclosures,pollution performance and economic performance

This study examines the association between pollution disclosures and pollution performance and between pollution disclosures and economic performance for firms in highly polluting industries. An index of pollution disclosures is developed and correlated with indices of pollution performance and economic performance. The results confirm earlier findings that there is no association between pollution disclosures and pollution performance. As far as the association between economic performance and pollution disclosures is concerned, the results show that the subgroup of large firms with poor economic performance provides the most detailed pollution information. For smaller firms there is no association between economic performance and pollution disclosures.     

Correlation bias in U.S. census adjustment

One form of error that can affect census adjustments is correlation bias, reflecting people who are doubly missing--from the census and from the adjusted counts as well. This article presents a method for estimating the total national number of doubly-missing people and their distribution by race and sex. Application to the 1990 U.S. census adjustment leads to an estimate of 3 million doubly-missing people. Correlation bias is likely to be a serious problem for census adjustment in 2000. The methods of this article are well suited for measuring its magnitude.     

A new class of measurement-error models,with applications to dietary data

Measurement-error modelling occurs when one cannot observe a covariate, but instead has possibly replicated surrogate versions of this covariate measured with error. The vast majority of the literature in measurement-error modelling assumes (typically with good reason) that given the value of the true but unobserved (latent) covariate, the replicated surrogates are unbiased for latent covariate and conditionally independent. In the area of nutritional epidemiology, there is some evidence from biomarker studies that this simple conditional independence model may break down due to two causes: (a) systematic biases depending on a person's body mass index, and (b) an additional random component of bias, so that the error structure is the same as a one-way random-effects model. We investigate this problem in the context of (1) estimating distribution of usual nutrient intake, (2) estimating the correlation between a nutrient instrument and usual nutrient intake, and (3) estimating the true relative risk from an estimated relative risk using the error-prone covariate. While systematic bias due to body mass index appears to have little effect, the additional random effect in the variance structure is shown to have a potentially important effect on overall results, both on corrections for relative risk estimates and in estimating the distribution of usual nutrient intake. However, the effect of dietary measurement error on both factors is shown via examples to depend strongly on the data set being used. Indeed, one of our data sets suggests that dietary measurement error may be masking a strong risk of fat on breast cancer, while for a second data set this masking is not so clear. Until further understanding of dietary measurement is available, measurement-error corrections must be done on a study-specific basis, sensitivity analyses should be conducted, and even then results of nutritional epidemiology studies relating diet to disease risk should be interpreted cautiously.     

BOOKS RECEIVED

McGoldrick, M., (Ed.). (1998). Re-visioning family therapy: Race, culture, and gender in clinical practice .
Minuchin, P., Colapinto, J., & Minuchin, S. (1998). Working with families of the poor .
Tasker. F. L., & Golombok, S. (1997). Grouping up in a lesbian family: Effects on child developement .
Marsh, D., & Magee, R. (1998). Etbical and legal issues in professional practice with families .
Freeman, J., Epston, D., & Lobovitz, D. (1997). Playful approaches to serious problems .     

Some roots of preference: Roles,activities and familial values

This paper examines some of the connecting links between modernization in a developing society, particularly urbanization and increased education for women, and preferences for number of children. Using 1973 Taiwan data, preferences for smaller families are found to be consistently related to modern attitudes and behavior in the three domains examined: intrafamilial husband-wife role relationships, extrafamilial activities of the wife, and familial and religious values relating the family to the larger institutional setting. Modernization of these attitudes, behaviors, and values has an impact on reproductive goals independent of their association with structural variables. The wife's outside activities and exposure to modern influences through the mass media are especially important linkages, having a particularly strong mediating effect in the education effect on preferences. Intrafamilial relations appear to be of less importance. Modernization of familial and religious values mediates between urbanization and family size preferences. The measure of preference used is a scale value which has been found in other research to be more predictive of reproductive behavior than the conventional single-valued statement of number of children wanted. As the level of contraceptive use rises in developing societies, family size preferences increasingly become a factor in birth rates, and understanding the sources of change in these preferences takes on added importance. The policy implications of these findings are discussed.