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Early Dashboard Results Skewed Until Quota Sampling Kicks In

Posted on: Tuesday, May 02, 2017

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Key Recommendations for Online Sampling

Posted on: Tuesday, October 25, 2016

Probability sampling remains the gold standard for producing results that are representative of target populations. So much so that non-probability methods typically try to emulate or mimic probability sampling where possible:   ..

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Intercept Surveys

Posted on: Tuesday, October 18, 2016

Where river sampling is typically a supplemental source of responses to panel surveys, intercept surveys gather all their responses by interrupting traffic to web sites. CivicScience, Google Consumer Surveys (GCS) and RIWI each intercept people in their everyday use of the web. CivicScience posts polls to web sites, GCS prompts readers to take a survey in order to advance to the second page of a news article, and RIWI captures visitors to mistyped non-trademarked domain names (among other methods) and shows them instead the first question of a short survey.  ..

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River Sampling

Posted on: Tuesday, October 11, 2016

People who are willing to be members of panels differ in many ways from people who aren’t. This too lessens the representativeness of panel research.  ..

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Sample Matching

Posted on: Tuesday, October 04, 2016

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Quota Sampling

Posted on: Tuesday, September 27, 2016

Given that effective sample size declines dramatically when the characteristics of the sample don’t approximate national representativeness, one method of improving non-probability sampling is quota sampling, dividing the sample into cells and recruiting to fill those cells. Once 51% of the responses are women, you stop letting additional women take the survey, for instance. In this way, you minimize the effect of weights.  ..

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Weighting Survey Results

Posted on: Tuesday, September 20, 2016

Some researchers believe that most sampling bias from convenience samples can be removed by weighting. Post-stratification weighting is typically done once the survey is complete to make the results more closely conform to the national totals for key demographic categories. Cell weighting is the simplest form of such weighting – for instance, group responses by demographic cells such as age and gender (men under 55, men 55+; women under 55, women 55+) then calculate the weight for each cell so that it reflects the target population’s proportions.   ..

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Convenience Sampling: A Technique for Surveying Low-Incidence Populations

Posted on: Tuesday, September 13, 2016

Convenience sampling is almost the exact opposite of probability sampling: there is no sampling frame, there is no external random selection - anyone who comes across the survey can answer it. The results can be quite disproportionate to the target population: for instance, one convenience survey we were sent to analyze was intended to be representative of U.S. adults in general, yet only 17% of the sample was 35 years old or older – in the total adult population, this group represents 69% of adults, making for a large sampling bias. ..

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Probability Online Panels

Posted on: Tuesday, September 06, 2016

A probability online panel selects candidates for participation through a probability sample (typically using Address Based Sampling) and then relentlessly invites candidates to join the panel. Panelists who lack Internet access are then provided computers or tablets along with Internet connectivity, so that they can participate. They are assumed to be representative of non-Internet households for at least some period after empanelment.  ..

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The Gold Standard: Probability Sampling

Posted on: Tuesday, August 30, 2016

While probability sampling is rarely used with online research, it helps to keep probability sampling in mind because many of the techniques to improve the representativeness of online surveys mimic or emulate the key characteristics of probability sampling. 

Probability sampling has two key requirements ..

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