Outline: Survey Research

I. Sampling

II. Survey Contents

I. Sampling from a Population

“Sampling is the process of selecting units (e.g., people, organizations) from a population of interest so that by studying the sample we may fairly generalize our results back to the population from which they were chosen.” Population - complete set of individuals having some

common characteristic – e.g., Australians

Sampling frame – subset of the population from which the sample is actually drawn – e.g., White pages

Sample – the set of people included in the study (i.e., selected from the sampling frame) – e.g., Every 1000th person in the white pages

Population and Sample

Population Sample

Use parameters to summarize features

Use statistics to summarize features

Inference on the population from the sample

Confidence Intervals

The problem is to use the sample to make inferences about the population

If we were to repeat the entire process of drawing a sample and computing the statistic many, many times, we would find that the statistic varies some

A confidence interval takes advantage of those variations and allows us to specify a range that probably contains the true value of the parameter Technically, for an X% confidence interval, the

parameter will fall inside the specified range X% of the time in repetitions of the study

Confidence intervals usually vary between 90% and 99.9%

Define a Population

The first step in choosing a sample is to define the population, or the overall set of cases that we’re interested in If we want to predict the results of an election,

then our population is “likely voters” If we want to understand who decides to vote,

then our population is “citizens eligible to vote” If we want to understand who decides to use

marijuana in the United States, our population is probably “everyone in the United States”

Nonprobability Sample Items included are chosen without

regard to their probability of occurrence

Probability Sample Items in the sample are chosen on the

basis of known probabilities

Types of Samples Used

Types of Sampling Methods

Samples

Non-Probability Samples

Convenience

Probability Samples

Simple Random Stratified Cluster

Quota

Probability Sampling

Members of the sample are chosen based on known probabilities

Probability Samples

Simple Random

Stratified Cluster

Simple Random Samples

Every individual or item from the frame has an equal chance of being selected

Selection may be with replacement or without replacement

Samples obtained from table of random numbers or computer random number generators

Stratified Samples

Population divided into two or more groups according to some common characteristic

Simple random sample selected from each group

The two or more samples are combined into one

Stratified Sampling Example

PopulationPopulation

Cash holdings of All Financial

Institutions in the United States

Large Institutions

Medium Size Institutions

Small Institutions

Stratified PopulationStratified Population

Stratum 1

Stratum 2

Stratum 3

Select n1

Select n2

Select n3

Financial Institutions

Cluster Samples

Population divided into several “clusters,” each representative of the population

Randomly select certain clusters The samples are combined into one

Population divided into 4 clusters.

Cluster Sampling Example

42 22 52

Illinois Scotland Florida

25 105 20 36 152 76 37

Algeria California Alaska New York Idaho Mexico Australia

Mid-Level Managers by Location for Morrison-Knudsen Construction Company

Cluster Sampling Example

42 22 52

Illinois Scotland Florida

Mid-Level Managers by Location for Morrison-Knudsen Construction Company

All members selected from these clusters

Types of Survey Errors

Coverage error

Non response error

Sampling error

Measurement error

Excluded from frame.

Follow up on non responses.

Chance differences from sample to sample.

Bad Question!

II. Survey Contents

Remember that your respondents will be “Lazy Thinkers.”

Survey Contents

When creating questions, consider the effects of the following elements: Type

Wording

Order

Content

Survey Contents: Type

Open-ended

A survey question to which the respondent replies in his or her own words, either by writing or by talking

difficult to analyze, subjective analysis

time consuming rich information useful for descriptive,

exploratory work

Closed-ended or fixed-choice

A survey question that provides preformatted response choices for the respondent to circle, check, mark, etc.

easier to analyze efficient useful for hypothesis

testing important info may be

lost forever

Closed-ended Questions

Closed-ended or fixed-choice Response options are limited

Yes/no True/false Multiple choice with an “other” option

Race: White, Black, Hispanic, Asian, Other Likert Scales 1 2 3 4 5

Strongly Agree Neither Disagree Strongly Agree A nor D Disagree

Rating Scales Ask respondents to rate something like a person, place, thing, idea,

attitude, etc. on a numbered scale, often Likert scales Semantic Differential a fifth grader is Bad GoodAwful ⊲ ⊲ ⊲ ⊲ Nice⊳ ⊳ ⊳ ⊳

Survey Contents: Wording

Guidelines for good questions:1. Be direct

2. Maintain simplicity

3. Be specific

4. Take the role of your respondent

The following points elaborate on these four main themes.

Survey Contents: Wording Respondents should understand your questions. No

complex rhetoric, syntax, or disciplinary slang or jargon. Pre-testing is a very effective way to see if they do

Do not expect them to learn new information just answer a question. (Sometimes, you may establish context with a short paragraph then ask a series of short, specific questions.)

Avoid ambiguous questions. “Do you teach your children to effectively function?” “Does your

boss engage you in interactive dialogue?” “Effectively function” and “interactive dialogue” are subject to interpretation.

Words such as "usually" or "normally" mean different things to different people. “Do your customers normally complain?” has a variety of interpretations.

Survey Contents: Wording

Avoid Double-barreled questions. They contain two questions in one. For example, “Do you think that students and Professors should be given discounts on sports tickets?”

Avoid Double-negative questions. For example, “Do you disagree that professors should not be required to help students outside of class?”

Avoid loaded questions. Avoid making one response option look more suitable than the other, using emotionally loaded terms, or using unbalanced response categories. “Don’t you think that suffering terminal cancer patients should be allowed

to be released from their pain by choosing death?” Virginia pays teachers more than similar states. Virginia should: spend

more, keep spending the same, reduce spending little, reduce spending some, reduce spending a lot, dramatically reduce spending

Survey Contents: Order

Relative placement of questions in the instrument

Opening questions should be simple and introduce the topic of the survey. Also put most important questions early.

Put closed-ended questions early in the survey and open-ended questions later.

Avoid a lot of “skipping” or “go to next section”. R’s will get confused/frustrated.

Survey Contents: Order

Try not to mix topics. Put like things into sets of questions. Clearly transition between types of questions.

Sensitive questions should never be at the beginning. Put in middle. May need opening paragraph for them.

Avoid framing later questions with topics that can be linked to them in previous questions. For example, one should not ask about attitudes toward crack use right before asking about attitudes toward the urban poor. This may invoke stereotypes about the poor.

Survey Contents: Content

Topics the questions cover

You should make the topic of the survey clear to R’s. Do not surprise them with questions about unrelated topics.

If including sensitive questions, provide a rationale for asking them. Explain how honest answers will be helpful to others and reassure confidentiality.

Questions relevant to deviance should include normalizing statements. For example, “Many people use drugs for a variety of reasons. Have you ever used ecstasy (or x, e, MDMA) to feel closer to other people?”

Questions that require lots of specific details or a good memory are typically useless. If they are necessary, employ techniques to prompt recollection.

Survey Contents General Advice

Always consult other surveys first

Always pre-test your instrument Consider these issues:

Consider “no opinion” as an option.

People want to appear to agree. Consider negative and positive statements.

R’s may lose track and choose salient options (such as first in series). Keep questions simple.

Response set problem

Survey Contents

Consider these issues: Bad memory leads to:

Forward telescoping (reporting that events occurred more recently than in reality)

Backward telescoping (reporting events further back than in reality).

Salient events are overreported Mundane events are underreported “Habitual” events will fill in for lost information.

Provide aides to recall such as reference points, landmark events, etc. Use limited time frames in questions.

Class Exercise

Split into groups

Select a topic for a survey

Develop 2 closed-ended and 2 open-ended questions. For each question, write a ‘poor’ version and a ‘good’ version

Administer the survey to member of another group. Critique each other’s questions