http://ehar.se/ Recent content in Demography and Statistics on Statistics and Demography Hugo -- gohugo.io en-us Tue, 02 Nov 2021 00:00:00 +0000 http://ehar.se/2021/11/02/f%C3%B6rv%C3%A4ntad-livsl%C3%A4ngd/ Tue, 02 Nov 2021 00:00:00 +0000 http://ehar.se/2021/11/02/f%C3%B6rv%C3%A4ntad-livsl%C3%A4ngd/ I krönikan “40 är det nya 25” (Bil & Bostad den 27 oktober 2021) ger Nicklas en förtjänstfull översikt av den demografiska utvecklingen under de senaste tvåhundra åren. Framförallt påvisas den dramatiska nergången i förväntad livslängd över tid. Men avslutningen, där det spekuleras i hur stor del av sitt liv en 40-åring har levat, osv, blir det fel. Nicklas tycks påstå att om förväntad livslängd ett visst år är 50, så har en 40-åring det året endast 10 år kvar att leva, i genomsnitt, men detta är helt fel! http://ehar.se/2021/03/14/temperature/ Sun, 14 Mar 2021 00:00:00 +0000 http://ehar.se/2021/03/14/temperature/ Reading temperature data (Updated 2021-03-16) We got temperature data from SMHI for central Umeå, daily measurements starting at 1 November, 1858 and ending at 30 September, 1979 (this particular weather station was replaced at this last date). Since we attempt to match these data to population data for the time period 1 January 1901 – 31 December 1950, we cut the temperature data to the same time period. http://ehar.se/2021/02/24/covid-19-v%C3%A4sterbotten-och-sverige-2020/ Wed, 24 Feb 2021 00:00:00 +0000 http://ehar.se/2021/02/24/covid-19-v%C3%A4sterbotten-och-sverige-2020/ Det senaste året, sedan coronaviruset började spridas i Sverige, har vi dagligen matats med information om hur många personer som har “dött med covid-19”. Notera att det står “med”, inte “av”, och skälet till detta är ju att alla som är smittade vid dödstillfället (eller tidigare) räknas, alldeles oavsett vad den verk liga dödsorsaken är. Vidare följer länderna i världen olika procedurer för rapportering, och sammantaget betyder det att det är svårt att göra meningsfulla jämförelser mellan länder och regioner i fråga om om var covid-19 har krävt flest dödsoffer. http://ehar.se/2020/05/17/random_intercepts/ Sun, 17 May 2020 00:00:00 +0000 http://ehar.se/2020/05/17/random_intercepts/ Model Consider a linear mixed model like \[\begin{equation} Y_{ij} = \alpha + u_i + \beta x_{ij} + \epsilon_{ij}, \quad j = 1, \ldots, n_i; \; i = 1, \ldots, K, \tag{1} \end{equation}\] where \(u_1, \ldots, u_K\) are iid random intercepts (drawn from \(N(0, \tau^2)\)), \(x_{ij}\) are measures on a covariate (continuous type) and \(\epsilon_{ij}\) are iid \(N(0, \sigma^2)\). If the \(u\)s and the \(x\)es are independent, we can write the model as http://ehar.se/2020/04/12/sexratio/ Sun, 12 Apr 2020 00:00:00 +0000 http://ehar.se/2020/04/12/sexratio/ I was looking at Swedish vital data from Statistics Sweden as a reaction to certain statistics floating around in the shadow of the ongoing covid-19 pandemic, when I accidentally happened to look at the age-specific sex ratio (males to females) in Sweden 2018, see Figure 1. Figure 1: Sex ratio by age, Sweden 2018. This is quite as expected, with the exception of the small peak at age 19. http://ehar.se/2018/08/30/short/ Thu, 30 Aug 2018 00:00:00 +0000 http://ehar.se/2018/08/30/short/ Slides are here. Comments are welcome! http://ehar.se/2017/04/27/sem0427/ Thu, 27 Apr 2017 00:00:00 +0000 http://ehar.se/2017/04/27/sem0427/ Slides are here. Comments are welcome! http://ehar.se/2016/12/19/mediation-in-survival-analysis/ Mon, 19 Dec 2016 00:00:00 +0000 http://ehar.se/2016/12/19/mediation-in-survival-analysis/ Introduction The estimation of direct effects and indirect effects (via one or several mediators) of an exposure on survival is a challenging task, that has received much attention lately. A good overview is given by Aalen et al. (2012). They emphazise the importance of explicitly including time in any discussion of causality and mediation: A cause must precede an effect. And many relevant references are found there. Relevant, recent material Tyler VanderWeele has written a lot of interesting stuff on mediation, look under “Selected Publications” and “Methodological” on his homepage. http://ehar.se/2016/12/19/sizeless/ Mon, 19 Dec 2016 00:00:00 +0000 http://ehar.se/2016/12/19/sizeless/ Sizeless statistics We were shown that the log-odds-ratio was 0.101 and the number of sigificance stars attached to it was three. But we were not told the subject-matter implication of this finding, other than that the “log odds” of migrating was larger in one group than in the other. But why is sizeless statistics so common today? This is an increasing problem in applied statistics, especially in the social sciences, since a couple of decades ago. http://ehar.se/2016/10/02/contrasts/ Sun, 02 Oct 2016 00:00:00 +0000 http://ehar.se/2016/10/02/contrasts/ 1 The problem 1.1 The cause 2 The solution 2.1 A related problem: The Hauck-Donner effect 2.2 Back to the main track: A simulation study 3 Conclusion References 1 The problem When I run a logistic regression on infant mortality with a categorical covariate, say season, with four categories, (‘spring,’ ‘summer,’ ‘fall,’ ‘winter’), with the following data (400 births), http://ehar.se/2016/09/23/aggregate/ Fri, 23 Sep 2016 00:00:00 +0000 http://ehar.se/2016/09/23/aggregate/ Introduction If you suffer from large execution times with huge data sets, and/or integrity problems, this is for you. I show how the theory of sufficient statistics may solve your problem, given that you are willing to organize your data properly. Your integrity problem (if any) is solved on the fly. I am illustrating everything by example using R and RStudio. However, the principle is universal, and you could, as an exercise, think of how you would implement it in Stata, if that is part of your inclinations. http://ehar.se/about/ Mon, 01 Jan 0001 00:00:00 +0000 http://ehar.se/about/ I am a docent in mathematical statistics and professor emeritus at the Centre of Demographic and Ageing Research (“CEDAR”) at Umeå University, Umeå, Sweden. http://ehar.se/r/ Mon, 01 Jan 0001 00:00:00 +0000 http://ehar.se/r/ The eha package. The Second Edition (2022) of Event History Analysis with R http://ehar.se/research/ Mon, 01 Jan 0001 00:00:00 +0000 http://ehar.se/research/ Broström, G. and Bengtsson, T. (2022). “Infant mortality and temperature, northern Sweden 1895–1950” Paper presented at the ESHD Conference, Madrid 2022. View Download. Edvinsson, S. and Broström, G. (2020). “Is high social class always beneficial for survival? A study of northern Sweden 1801–2013." (Updated 2020-06-26 13:35) View Download.