Gompertz mortality models: the relationship between alpha, beta and mode age

Introduction The Gompertz model is one of the most well-known mortality models. It does remarkably well at explaining mortality rates at adult ages across a wide range of populations with just two parameters. This post briefly reviews the Gompertz model, highlighting the relationship between the two Gompertz parameters, (\alpha) and (\beta), and the implied mode age at death. I focus on the situation where we only observe death counts by age (rather than mortality rates), so estimation of the Gompertz model requires choosing (\alpha) and (\beta) to maximize the (log) density of deaths.

Using SVD in demographic modeling

A core objective of demographic modeling is finding empirical regularities in age patterns in fertility, mortality and migration. One method to achieve this goal is using Singular Value Decomposition (SVD) to extract characteristic age patterns in demographic indicators over time. This post describes how SVD can be used in demographic research, and in particular, mortality estimation. Background The SVD of matrix (X) is [ X = UDV^T ] The three matrices resulting from the decomposition have special properties:

Comparing methods for smoothing temporal demographic data, and the distortr package

At the International Population Conference of the International Union for the Scientific Study of Population (IUSSP) I will present work on comparing different methods for smoothing demographic data. This post briefly outlines the motivation for the project and describes the R package distortr which accompanies the project. Motivation An important part of demographic research is the ability to estimate and project time series of demographic and health indicators. However, it is often the case that populations that have the poorest outcomes also have poor-quality data.

Text analysis of migration news articles

Leslie Root and I did some exploratory text analysis of migration-related newspaper articles in the US. We analyzed almost 10,000 articles over the period 2008-2017, looking at how topics and sentiment about migration have changed. Our initial analysis suggests that sentiment in migration news coverage has changed over time, and decreased since 2013. Major topics in migration news include political campaigns, the economy, illegal immigrants, Europe, and more recently, Donald Trump.

Opioid mortality by race: from divergence to convergence

Opioid-related mortality in the United States has been rising steadily since 2000. The opioid mortality rate has more than tripled since over the fifteen year period 2000–2015, and shows no signs of declining — in fact, the rate of increase has accelerated in recent years. This is unique to opioid-related drug deaths, with the non-opioid mortality rate remaining fairly level since 2005. The so-called ‘opioid epidemic’ has gained national attention and become an important part of the political agenda.

Distinguishing between real differences and model artefacts in mortality inequality research

A couple of weeks ago, a paper was published in the JAMA detailing income inequalities in mortality across cities in the United States. The research, which was led by Raj Chetty at Stanford University, received wide attention. It is an important contribution to the literature, utilizing detailed income and mortality data from the IRS and SSA to estimate adult mortality by income at the city level. The most striking finding of the research was that, while the rich live longer everywhere, life expectancy for those in the poorer income groups varies substantially by geography.

The Cost of NBA Games

I moved to the Bay Area almost three years ago, just in time to see the Golden State Warriors start to get pretty good. And then they got really, really, good. Being the serious, hardworking PhD student that I am, following the Warriors became a hobby. Turns out that this hobby, while healthier than drugs, may not be any cheaper. I grabbed all data on resale tickets from StubHub for all remaining games of the 2015-16 season.