A Novel Time Series Approach to Bridge Coding Changes with a Consistent Solution Across Causes of Death

Revisions of the International Classification of Diseases (ICD) can lead to biases in cause-specific mortality levels and trends. We propose a novel time series approach to bridge ICD coding changes which provides a consistent solution across causes of death. Using a state space model with interventions, we performed time series analysis to cause-proportional mortality for ICD9 and ICD10 in the Netherlands (1979–2010), Canada (1979–2007) and Italy (1990–2007) on chapter level. A constraint was used to keep the sum of cause-specific interventions zero. Comparability ratios (CRs) were estimated and compared to existing bridge coding CRs for Italy and Canada. A significant ICD9 to ICD10 transition occurred among 13 cause of death groups in Italy, 7 in Canada and 3 in the Netherlands. Without the constraint, all-cause mortality after the classification change would be overestimated by 0.4 % (NL), 0.03 % (Canada) and 0.2 % (Italy). The time series CRs were in the same direction as the bridge coding CRs but deviated more from 1. A smooth corrected trend over the ICD-transition resulted from applying the time series approach. Comparing the time series CRs for Italy (2003), Canada (1999) and the Netherlands (1995) revealed interesting commonalities and differences. We demonstrated the importance of adding the constraint, the validity of our methodology and its advantages above earlier methods. Applying the method to more specific causes of death and integrating medical content to a larger extent is advocated.     

Grandparents Responsible for Grandchildren in Native‐American Families*

Objectives. The primary goal of this article is to examine factors associated with grandparent care giving within the American Indian/Alaska Native (AIAN) population. Methods. Data from the 2000 Census of Population, 5% Public Use Microdata Sample, are used to evaluate a multivariate logistic regression model focusing on living with and caring for grandchildren. Particular emphasis is placed on characteristics that may reflect culturally‐based ideas about grandparents' responsibility for the care of their grandchildren. Results. Indicators related to Native‐American identity—specifically, reporting race as AIAN only rather than mixed race, reporting tribal membership, and living in a nonmetropolitan area of an “Indian” state—increase the likelihood of being responsible for a grandchild among Native‐American singles and couples aged 45 and over. Conclusions. Cultural and resource characteristics combine to produce high levels of grandparent care giving within the AIAN population. Inasmuch as those with lower educational and economic resources are especially likely to have responsibility for a grandchild, special attention should be directed toward ensuring adequate support for these caregivers.     

Remarks of a Polish praxiologist on the subject of a paper by C. Gutiérrez

Most theories of human action investigated primarily with respect to its efficiency, which came into existence during the last nearly 100 years (some of which have been christened by their authors praxeology or praxiology) are empirical ones. Prof. Gutiérrez' elegant critique of the extraordinary claim of praxeology to have an aprioristic character should be thus limited to v. Mises' (exceptional among other praxeologists) aprioristic approach. In any case that critique does not apply to the Polish school of Praxeology founded by T. Kotarbiski.     

Brokering Interests: The Use of Market-Based Policies by Interest Groups

Objective. This article begins the process of broadly evaluating the role of nongovernmental actors in regulatory markets by specifically examining environmental groups’ use of the sulfur dioxide (SO2) market established by Title IV of the Clean Air Act Amendments of 1990. This research posits that the use of nonexclusionary markets in environmental quality regulation allows interest groups a nonpareil opportunity to seek to directly affect policy outcomes. Methods. This article uses two forms of analysis. The first part of the article provides a qualitative analysis of the motives of interest groups that use incentive‐based policies in an attempt to achieve their desired policy outcomes. The last section of the article uses empirical data from the Environmental Protection Agency's Allowance Tracking System to evaluate interest groups’ use of market‐based policies. Results. The use of market‐based mechanisms in public policies offers interest groups a new form of participation in the policy process, yet it seems that only “new” groups are willing to enter the market. Further, I find that though the participating groups may not be able to affect the relative price of allowances (as they claim they will), they nonetheless are able to reduce the absolute number of allowances available. Finally, using market‐based policies to achieve their preferred outcomes may be a “rational” decision for groups in that the “return” on their investment may indeed be quite high. Conclusions. One aspect of pollution markets is clear—they do create an interesting new mechanism of public activism for groups that wish to protect the environment but do not want to “lobby or litigate.” By purchasing pollution allowances groups attempt to directly affect environmental policy outputs without entering the policy cycle as it has been previously understood. As market‐based policies are employed more broadly, opportunities accorded to environmental groups for active involvement in seeking to limit ambient pollutants, as well as the groups’ potential impact, may only expand.     

Testing the equality of several means when the population variances are unequal

A comparative study is made of three tests, developed by James (1951), Welch (1951) and Brown & Forsythe (1974). James presented two methods of which only one is considered in this paper. It is shown that this method gives better control over the size than the other two tests. None of these methods is uniformly more powerful than the other two. In some cases the tests of James and Welch reject a false null hypothesis more often than the test of Brown & Forsythe, but there are also situations in which it is the other way around.

We conclude that for implementation in a statistical software package the very complicated test of James is the most attractive. A practical disadvantage of this method can be overcome by a minor modification.     

Generalized Kernel Estimators for the Weibull-Tail Coefficient

We introduce new families of estimators for the Weibull-tail coefficient, obtained from a weighted sum of a power transformation of excesses over a high random threshold. Asymptotic normality of the estimators is proven for an intermediate sequence of upper order statistics, and under classical regularity conditions for L-statistics and a second-order condition on the tail behavior of the underlying distribution. The small sample performance of two specific examples of kernel functions is evaluated in a simulation study.     

Invertibility of non-linear time series models

Sufficient conditions for invertibility of non-linear time series models are available in the literature only for a few special cases. In this paper a practical and general method for checking invertibility is presented. Briefly stated, it consists of feeding independent and identically distributed innovations into the non-linear model and then observing whether the model blows up or not. Using this idea invertibility conditions are derived for several recently proposed non-linear moving average models. Finally, the method is applied to a number of bilinear models fitted to economic time series.     

Variance Estimators of the Gini Coefficient—Probability Sampling

An estimator of the Gini coefficient (the well-known income inequality measure) of a finite population is defined for an arbitrary probability sampling design, taking the sampling design into consideration. Alternative estimators of the variance of the estimated Gini coefficient are introduced. The sampling performance of the Gini coefficient estimator and its variance estimators is studied by means of a Monte Carlo study, using stratified sampling from a miniature population of Swedish households with authentic income data.