# Complex Survey

### Member Training: A Quick Introduction to Weighting in Complex Samples

October 3rd, 2017 by

A few years back the winning t-shirt design in a contest for the American Association of Public Opinion Research read “Weighting is the Hardest Part.” And I don’t think the t-shirt was referring to anything about patience!

Most statistical methods assume that every individual in the sample has the same chance of selection.

Complex Sample Surveys are different. They use multistage sampling designs that include stratification and cluster sampling. As a result, the assumption that every selected unit has the same chance of selection is not true.

To get statistical estimates that accurately reflect the population, cases in these samples need to be weighted. If not, all statistical estimates and their standard errors will be biased.

But selection probabilities are only part of weighting. (more…)

### Target Population and Sampling Frame in Survey Sampling

February 9th, 2015 by

Author: Trent Buskirk, PhD.

As it is in history, literature, criminology and many other areas, context is important in statistics.  Knowing from where your data comes gives clues about what you can do with that data and what inferences you can make from it.

In survey samples context is critical because it informs you about how the sample was selected and from what population it was selected.   (more…)

### What is a Complex Sample Part 2: What is it and Why Would You Ever Want to Use One?

January 6th, 2014 by

In our last article, we talked about simple random samples.  Simple random samples are, well…simple, but they’re not always optimal or even possible.

Probability samples that don’t meet the assumptions of Simple Random Samples are called Complex Samples.

You’ll also hear the term Complex Survey, which is really just a survey that incorporates some sort of complex sampling design.  Because of their size and research goals, surveys are usually* the only type of research study that uses complex samples.

(*but not always.  I have seen intervention studies, for example, that used complex sampling).

### What is a Complex Sample?

The most defining feature of a complex sample is that sample members do not have equal probability of being selected.

That sounds simple enough.  But… (more…)

### Member Training: Complex Survey Sampling – An Overview

November 1st, 2013 by

Complex Surveys use a sampling technique other than a simple random sample. Terms you may have heard in this area include cluster sampling, stratified sampling, oversampling, two-stage sampling, and primary sampling unit.

Complex Samples require statistical methods that take the exact sampling design into account to ensure accurate results.

In this webinar, guest instructor Dr. Trent Buskirk will give you an overview of the common sampling techniques and their effects on data analysis.

Note: This training is an exclusive benefit to members of the Statistically Speaking Membership Program and part of the Stat’s Amore Trainings Series. Each Stat’s Amore Training is approximately 90 minutes long.

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