Authors’ response: on the role of data,statistics and decisions in a pandemic

AStA Advances in Statistical Analysis -     

Nonparametric estimation of the lower tail dependence λL in bivariate copulas

The lower tail dependence λ_L is a measure that characterizes the tendency of extreme co-movements in the lower tails of a bivariate distribution. It is invariant with respect to strictly increasing transformations of the marginal distribution and is therefore a function of the copula of the bivariate distribution. λ_L plays an important role in modelling aggregate financial risk with copulas. This paper introduces three non-parametric estimators for λ_L. They are weakly consistent under mild regularity conditions on the copula and under the assumption that the number k = k(n) of observations in the lower tail, used for estimation, is asymptotically k ≈ √n. The finite sample properties of the estimators are investigated using a Monte Carlo simulation in special cases. It turns out that these estimators are biased, where amount and sign of the bias depend on the underlying copula, on the sample size n, on k, and on the true value of λ_L.     

Do female candidates ‘lose votes’?: the experience of female candidates in the 1979 and 1980 Canadian general elections

Dans quelle mesure la sous-représentation des femmes au Parlement du Canada est-elle attribuable à la “perte de votes”? II est évident que lorsque les femmes se présentent à la députation sur un pied d‘égalité avec les hommes en ce qui concerne un rival titulaire, la compétitivité du siège disputé, et le parti politique, les femmes n'obtiennent pas moins de votes que les hommes. Les femmes sont également plus aptes àêtre choisies pour disputer des sièges à des titulaires ou des sièges que le parti a peu ou pas de chance de gagner. II est done peu probable que l’échec relatif des femmes aux élections fédérates soit directement relié aux sentiments des électeurs. II apparait plutôt que le succès limité des femmes dans la politique fédérale au Canada est dû aux difficultés qu'elles ont à se faire nommer pour disputer des sièges qu'elles auraient une assez bonne chance de gagner. This paper explores the extent to which the under-representation of women in the House of Commons in Canada can be attributed to female candidates “losing votes.” The evidence suggests that, when male and female candidates are equated in terms of running against an incumbent, competitiveness of the contested seat, and political party, the women do not receive fewer votes than the men. At the same time, women were more likely than men to be nominated to contest seats against incumbents or seats which their party had little or no chance of winning. It does not seem, then, that the relative failure of women in federal elections can be traced directly to voters' sentiments. Rather, it appears as if the limited success of women in federal politics in Canada largely originates in their difficulties in securing nominations to contest seats which they have some reasonable prospect of winning.     

Accounting for the Value of Performance Measurement from the Perspective of Midwestern Mayors

This article studies the decades-long question, "Does performancemeasurement matter?" by examining how and why Midwest mayorsperceive value in performance measurement. The results showthat the tool is perceived positively, but its impact on decisionmaking depends on whether performance measurement is integratedinto strategic planning, goal setting, and internal communicationbetween city council members and departmental staff and on whethermajor stakeholders are involved in developing performance measures.The article discusses the implications for future results-orientedreforms and concludes that simply reporting performance informationin budgetary or public documents is not enough. Rather, a morecomprehensive look at the implementation issues of performancemeasurement and performance budgeting is necessary.     

Gluing Copulas

We present a new way of constructing n-copulas, by scaling and gluing finitely many n-copulas. Gluing for bivariate copulas produces a copula that coincides with the independence copula on some grid of horizontal and vertical sections. Examples illustrate how gluing can be applied to build complicated copulas from simple ones. Finally, we investigate the analytical as well as statistical properties of the copulas obtained by gluing, in particular, the behavior of Spearman's ρ and Kendall's τ.     

Implementing integrated pest management in professional lawn care: a case study

Human choices regarding land cover management practices may influence ecosystem services provided by urban green spaces. We conducted a 2-year study to compare biological (weed, insect, and disease), aesthetic (lawn quality), and economic (lawn care program cost) attributes of an integrated pest management (IPM) program, in which pesticides are applied on the basis of treatment thresholds, with a standard program, in which pesticides are applied on a calendar basis without pest monitoring. Both programs were managed by a professional lawn care operator. Although weed incidence was low, the IPM program had significantly more lawns with weed presence than the standard program during 2005 and 2006. However, only 21% of the IPM lawns required herbicide applications in 2005, and none exceeded the treatment threshold (5% weed cover) in 2006 as compared to 100% of the standard program lawns being treated for weeds in both years. The IPM program also had significantly more lawns with insect damage than the standard program during June 2005 and August 2005, but not September 2005 and throughout 2006. Only 28% of the IPM lawns required insecticide applications in 2005 and none exceeded the threshold (5% insect damage) in 2006 whereas all of the lawns in the standard program received insecticide treatments in both years. Rhizoctonia blight was present on some of the lawns, but was not a common problem. Although lawn quality was high for both programs (>8, on a scale of 1–9), it was significantly higher for standard than for IPM program lawns during 2005, and June 2006 and September 2006, but not August 2006. The annual lawn management costs were lower for the IPM (281.50) than the standard program (281.50) than the standard program (458.06). Thirty one percent of the IPM program customers who continued with the study in 2006 did so because they were satisfied with the IPM program. Among those who did not continue with the program, 33% cited weed or insect problems, while 33% expected better results. The implications of these findings for implementation of IPM in professional lawn care are further discussed.     

A study on the effectiveness of sterilizations in reducing the birth rate

This study analyzed 1,081 women in Kerala State (India) who were either sterilized or were the wives of sterilized men, and by examining the fertility among a comparable group of 1,000 other women, estimated the number of prevented future births per 1,000 women in the sterilized group. The results of this estimation were then applied to project what the entire savings in births might be over a 3D-year period in the entire Kerala population if each year there were one, three, or five sterilizations performed per 1,000 of total population. The results failed to confirm the hope that the crude birth rate would be decreased by 12 per 1,000 in a decade merely by sterilization of five per 1,000 of the population per annum. The study also discusses various measures of reduction in the crude birth rate. By a reasonable measure, the reduction in the crude birth rate for Kerala from such a sterilization program is estimated as seven points after a decade or nine points after three decades, reflecting decreases of 21 and 36 per cent, respectively, in the number of births.