In my job this kind of models are our daily bread. Item response theory models are used to asses the quality of education, and if you are serious about educational or psychological measurement, this kind of models are mandatory. First of all, IRT models are just that: stochastic models. There is nothing mysterious behind them, because … Sigue leyendo Item Response Theory Models in R and JAGS: simulation and bayesian estimation of 1PL models
Etiqueta: Stats
Reporting survey estimates: coefficient of variation and lower confidence interval bound
I had already posted something on this sort before (click here) and I want to discuss on something else. In Colombia, for example, some official statistics institutions claim that any survey estimate with an estimated coefficient of variation (CV) greater than 15% is not reliable and, although it is published, the very figure is marked … Sigue leyendo Reporting survey estimates: coefficient of variation and lower confidence interval bound
Power of a Test and Sample Size in Complex Surveys
There are many approaches to computing sample size. In public policy evaluation, for example, one is usually tented to check if there is statistical evidence on the impact of a intervention over a population of interest. This vignette is devoted to explain the issues that you commonly find when computing sample sizes.You may have been … Sigue leyendo Power of a Test and Sample Size in Complex Surveys
Making maps in R with ggplot
This post is devoted with the quick (and free) solution of a problem that maybe some statisticians face in their jobs. Maps are becoming a valuable tool of information and you will find that R could be a comprehensive solution for this type of task.You will need to distinguish two types of data: the cartography … Sigue leyendo Making maps in R with ggplot
Our paper in Survey Methodology
As a result of a comprehensive research about gross flows and survey sampling, we have been published in Survey Methodology. The paper presents a new methodology for the proper estimation of gross flows when using complex samples.
Reproducibility: our biggest concern as statisticians
What do identify scientists? In a nutshell, if you claim yourself as a scientist, your scientific results must be reproducible and they could be replicated. That’s it.In my consulting work, I’ve had this concern since the very first moment. It would be not surprise anybody that as statistician we concern about reproducibility. However, I’ve noticed … Sigue leyendo Reproducibility: our biggest concern as statisticians
Leslie’s Advice on Statistical Design
An old issue of Statistical Science includes an interview with Leslie Kish by Frankel and King. Leslie was the most influential statistician in the field of Survey Sampling and Statistical Design in the past century. I wan to stress out these words of mere wisdom: Now we are at a very important point. How does statistical … Sigue leyendo Leslie’s Advice on Statistical Design
DEFF is an ex-ante measure
The Design Effect is measure of efficiency defined as the ratio between two sampling variances: $$DEFF=\frac{Var1}{Var2}.$$Before discussing the design effect properties, it is necessary to define what a sampling strategy is. This is a pair composed of an estimator (of a single parameter of interest) and a probability measure (or sample design). In the computation … Sigue leyendo DEFF is an ex-ante measure
LaTeX for statisticians
What do successful statisticians do in real life? I think that success relies in effective communication. All of the time, we are in broadcast mode: our ideas, results and analysis yield to decision making and it is up to us to find compelling ways to seed our beliefs in those statistical analyses into the mind … Sigue leyendo LaTeX for statisticians
LaTeX for Statisticians (Our course in USTA)
What do successful statisticians do in real life? I think that success relies in effective communication. All of the time, we are in broadcast mode: our ideas, results and analysis yield to decision making and it is up to us to find compelling ways to seed our beliefs in those statistical analyses into the mind … Sigue leyendo LaTeX for Statisticians (Our course in USTA)
Why we do not experiment with people in surveys?
Today I was giving a lecture on sample surveys and observational studies. When I was saying that surveys involving people are only observational and do not take part into the experimental world, some people refused to accept that fact. They argued that some researchers actually do experiments with people in the context of public policy. … Sigue leyendo Why we do not experiment with people in surveys?
Common support graphics in propensity score matching (using ggplot2)
Common support is a must check when doing impact evaluation of public policies (or - more widely - when verifying the causation of some factors over a population). The seminal paper of Rosenbaum and Rubin (1983) defines the propensity score as a measure of balance. Moreover, when doing matching, we must assure that propensity scores … Sigue leyendo Common support graphics in propensity score matching (using ggplot2)
Muestreo, encuestas y estadísticas oficiales 