3: Evaluating Frequency Claims

Question 1

Interrogating construct validity

Answer 1

Empirical reliability:

• test-retest: stable variables
• inter-rater: observational
• internal: self report

Subjective:

• have face validity?
• tap into all aspects of variable (content)?

Empirical evidence construct:

• quantitative or categorical(criterion validity)?
• correlate with measured (convergent) or with measures of other variables (discriminant)?

Question 2

Interrogating external

Answer 2

-attend to method of recruitment and sampling
-potential for sampling bias? How were recruited?
•was convenience?
•other techniques?
•do recruiting cover targeted population?

Potential for volunteer bias? Who is particpatents?
•self election result in non-response bias?

Question 3

Problems with telephone sampling

Answer 3

-using phone book =sampling bias
•individuals with and without landline diff
-even including cell phones =low response rates and introduce (non)-response bias
•those who answer diff from those who don’t

Question 4

Internet research

Answer 4

-nonrandom sampling:
•sampling bias: internet access, know how to use, internet-savvy
•volunteer bias: self selected opt-in

-from internet and not internet may be diff
•may be a problem for sensitive or hot button issues

Question 5

Interrogating stat validity of frequency

Answer 5

• proportion at specific value of variable (rate) and margin of error
• mean value of specific variable (level) and standard error

•large sample size: smaller margin of error
-reflects more confidence in population
- sample size formulas
•use an economic sample size
-even for national popualtions, should not large
-only enough to ensure acceptable error

Question 6

Sample size doesn’t equal external validity

Answer 6

• larger samples not neccassarily more representative
• reflects degree to which sample was randomly selected and looks like POI not sample size

-once external established, increasing sample size decreases margin of error
•don’t nothing for biases (sampling or response)

Question 7

1936 presidential election

Answer 7

Landon v Roosevelt
-mailed block ballots to a mailing list of 10 mil American voters
•1/4 voting population
-2.3 mil responses, Landon (R) would win
-FDR won handily

Dewey v Truman
-Gallup poll trained interviewers to meet demo quotas
•pollster chose who to interview
-dewy defeats Truman