A brief note on measurement error in family fixed-effects models

TL;DR: within-family models have been argued to suffer from a magnification of attenuation bias compared to between-family models. However, this is only true under the assumption of uncorrelated measurement errors. This is not very realistic, and under reasonable conditions it is possible that within-family models actually suffer from less attenuation bias than between-family models. Family… Continue reading A brief note on measurement error in family fixed-effects models

Natural experiments and the Coronavirus: a dose of methodological caution

With Ariel Young The impact of the coronavirus is steadily growing to become the most devastating disaster in a half century, in terms of the cost to human life as well as the economic and social impact it has had around the world. In just nine months since the outbreak began in January 2020, at… Continue reading Natural experiments and the Coronavirus: a dose of methodological caution

Avoid these mistakes with interaction models

When we’re trying to statistically work out whether a correlation, effect or treatment outcome is particularly strong (or even whether the sign varies) among certain types of units or is dependent on some other variable, we typically use interaction models – and more specifically, multiplicative interaction terms in some linear regression framework. Interaction models, like… Continue reading Avoid these mistakes with interaction models

Be careful with cross-country variation in self-rated health.

Measures of self-reported health status are generally considered fairly accurate measures of underlying “real” health status (measures of self-rated health (SRH) are, for example, predictive of subsequent mortality). Typical SRH items will ask a respondent something along the lines of “In general, how is the state of your health these days?” with a Likert response… Continue reading Be careful with cross-country variation in self-rated health.

Would Clinton and Trump have been better off running in the 18th century?

There is currently massive media coverage of the health status of the two American presidential candidates. Hillary Clinton contracting pneumonia and appearing weak at the 911 memorial ceremony, and Donald Trump revealing doctor’s documents showing that he is bordering on obese and takes cholesterol-lowering drugs, have almost completely overshadowed more substantial political issues in the… Continue reading Would Clinton and Trump have been better off running in the 18th century?

Are Swedish authorities sloppy when designing ballot papers? Evidence from an RDD.

I’ve been digging into some (actually, lots of) data on ballot layout and preference voting from the Swedish electoral authority, Valmyndigheten, recently, mainly as a way of practicing my RDD-skills. In the process I’ve come across some funky results that I have a hard time getting my head around, which has led me to contemplate:… Continue reading Are Swedish authorities sloppy when designing ballot papers? Evidence from an RDD.

No – the sign of your correlation doesn’t mean anything either

Here is a generic version of a conversation I’ve had a few too many times: Person 1: “Hey look what I found! My favourite theory is consistent with this correlation. This thing is positively related to that thing.” Person 2: “Good for you! Correlation doesn’t imply causation, though, right?” Person 1: “Of course not, don’t… Continue reading No – the sign of your correlation doesn’t mean anything either