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Topic

Statistics

A collection of 123 issues

Reconceptualizing the Effect of the Deliberative Poll

Deliberative Poll proceeds as follows: Respondents are surveyed, provided ‘balanced’ briefing materials, randomly assigned to moderated small group discussions, allowed the opportunity to quiz experts or politicians in plenary sessions, and re-interviewed at the end. The “effect” is conceptualized as the average Post–Pre across all participants. The effect of

Weighting to Multiple Datasets

Say there are two datasets—one that carries attitudinal variables, and demographic variables (dataset 1), and another that carries just demographic variables (dataset 2). Also assume that Dataset 2 is the more accurate and larger dataset for demographics (e.g. CPS). Our goal is to weight a dataset (dataset 3)

Size Matters, Significantly

Achieving statistical significance is entirely a matter of sample size. In the frequentist world, we can always distinguish between two samples if we have enough data (except of course if the samples are exactly the same). On the other hand, we may fail to reject even large differences when sample

Adjusting for Covariate Imbalance in Experiments with SUTVA Violations

Consider the following scenario: control group is 50% female while the participant sample is 60% female. Also, assume that this discrepancy is solely a matter of chance and that the effect of the experiment varies by gender. To estimate the effect of the experiment, one needs to adjust for the

Poor Browsers and Internet Surveys

Given, 1. Older browsers are more likely to display the survey incorrectly. 2. The type of browser can be a proxy for the respondent’s proficiency in using computers, and the speed of the Internet connection. People using older browsers may abandon surveys at higher rates than those using more

Reducing Errors in Survey Analysis

Analysis of survey data is hard to automate because of the immense variability across survey instruments—different variables, differently coded, and named in ways that often defy even the most fecund imagination. What often replaces complete automation is ad-hoc automation—quickly coded functions, e.g., recoding a variable to lie

Cricket: An Unfairly Random Game?

In many cricket matches, it is claimed that there is a clear advantage to bowling (batting) first. The advantage is pointed to by commentators, and by captains of the competing teams in the pre-toss interview. And sometimes in the post-match interview. The opportunity to bowl or bat first is decided

help(R): matrix indexing

In R, some want to treat matrix like a data frame. It is a bad idea. And no – one cannot use the dollar sign to pick out a column of a matrix. The underlying data structure for a matrix in R is a vector, whereas data.frame object in R

GSS and ANES: Alike Yet Different

The General Social Survey (GSS), run out of National Opinion Research Center at University of Chicago, and American National Election Studies (ANES), which until recently ran out of University of Michigan’s Institute for Social Research, are two preeminent surveys tracking over-time trends in social and political attitudes, beliefs and

The Perils of Balancing Scales

Randomization of scale order (balancing) across respondents is common practice. It is done to ‘cancel’ errors generated by ‘satisficers’ who presumably pick the first option on a scale without regard to content. The practice is assumed to have no impact on the propensity of satisficers to pick the first option,