# Presentation: 406680

## What Does “No Opinion” Mean in the HINTS?

***Michael P. Massagli, Ph.D. ***
-  K. Vish Viswanath, Ph.D.
- Dana-Farber Cancer Institute

## “There has been little formal research on the use of knowledge questions” (in surveys) – Sudman and Bradburn, 1982:117.

- Common Practices (e.g. Fowler, 1995: 67-69)
- Ask for a self-evaluation of knowledge
- True-false questions
- Multiple choice questions
- Open-ended short-answer questions

## Self-Evaluation

- How much would you say you know about the relationship between smoking and cancer – a lot, some, a little, or nothing at all?
- Do you think that smoking increases a person’s chances of getting cancer – yes or no?

## True-False

- Smoking increases a person’s chance of getting cancer – true or false?

## Multiple-Choice

- Which of the following is most likely to increase a person’s chance of getting cancer - Smoking, Being hit in the breast, Having a family history of cancer, or Pesticides?
- Which of the following is least likely to increase a person’s chances of getting cancer – smoking, exposure to the sun, pollution, or none of the above?

## Open-ended Short-answer

- Please tell me the things you are sure will increase a person’s chances of getting cancer?

## Issues for the Question Designer - I

- What kind of knowledge (active, specific) and how much?
- Difficulty of questions – will affect estimates, distribution of population
- Recognition vs.. recall; open-ended; plausibility of multiple-choice options
- Perceived threat
- False positives
- Explicit offer of ‘don’t know’?

## Issues for the Question Designer - II

- Cueing
- Information to frame adequate answers vs.. help getting correct answer
- Reliability
- Multiple-items and inter-item relationships
- Is there a latent variable? How do items relate to it?
- Item universe, sampling
- Number of items
- Response options
- Index vs.. scale

## HINTS CK13 questions: “I’m going to read you some things that may affect a person’s chances of getting cancer.  Do you think that [ X ] increase(s) a person’s chances of getting cancer a lot, a little, or not at all or do you have no opinion? [Don’t know and refused taken if volunteered; respondents randomly assigned to list A or B]

## HINTS CK-14:  Tell me how much you agree or disagree with the following statements, or if you have no opinion.

- It seems like almost everything causes cancer.
- There’s not much people can do to lower their chances of getting cancer.
- There are so many different recommendations about preventing cancer, it’s hard to know which ones to follow.
- Would you say you strongly agree, somewhat agree, somewhat disagree, strongly disagree, or you have no opinion?

## Relative Frequency Distribution – CK13 (A list)

| N=3,204 | A lot | A little | Not at all | No opinion | Refused | Don’t Know |
| --- | --- | --- | --- | --- | --- | --- |
| Smoking | 84.7 % | 9.0 | 1.2 | 4.7 | 0.0 | 0.3 |
| Pesticides or food additives | 41.4 % | 38.5 | 3.2 | 16.0 | 0.0 | 1.0 |
| Not eating much fiber | 33.6 % | 34.2 | 8.1 | 22.2 | 0.1 | 1.9 |
| Stress | 36.3 % | 31.8 | 15.2 | 15.6 | 0.0 | 1.1 |
| Being hit in the breast (n=1,912) | 15.8 % | 28.0 | 29.3 | 24.5 | 0.0 | 2.4 |
| Having a family history of cancer | 75.7 % | 18.9 | 2.2 | 2.8 | 0.1 | 0.3 |
| Not getting much exercise | 27.3 % | 47.0 | 13.4 | 11.2 | 0.0 | 1.0 |

## Relative Frequency Distribution – CK13 (B list)

| N=3,165 | A lot | A little | Not at all | No opinion | Refused | Don’t Know |
| --- | --- | --- | --- | --- | --- | --- |
| Eating a high-fat diet | 31.4 % | 30.8 | 8.9 | 27.3 | 0.0 | 1.6 |
| Exposure to the sun | 66.4 % | 26.1 | 2.1 | 4.9 | 0.1 | 0.5 |
| Not eating many fruits and vegetables | 42.7 % | 33.2 | 10.6 | 12.4 | 0.0 | 1.2 |
| Drinking a lot of alcoholic beverages | 41.6 % | 29.1 | 11.5 | 16.3 | 0.0 | 1.4 |
| Having many sexual partners (n = 1,933) | 42.5 % | 16.7 | 18.6 | 20.2 | 0.1 | 1.2 |
| Being a particular race or ethnicity | 13.3 % | 33.0 | 25.1 | 26.2 | 0.0 | 2.4 |
| Pollution | 57.2 % | 32.1 | 3.3 | 6.9 | 0.0 | 0.5 |
| Radon | 46.1 % | 26.6 | 3.3 | 21.5 | 0.1 | 2.4 |

## Relative Frequency Distribution – CK14 ( A vs. B list)

|  |  | Strongly agree | Somewhat agree | Somewhat disagree
 | Strongly disagree
 | Have no opinion
 | Refused
 | Don’t know
 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| It seems like almost everything causes cancer | A | 8.8 % | 35.3 | 27.7 | 16.3 | 11.5 | 0.1 | 0.3 |
|  | B | 11.5 % | 35.9 | 26.3 | 15.1 | 10.9 | 0.0 | 0.3 |
| There’s not much people can do to lower their chances of getting cancer | A | 5.3 % | 20.9 | 31.0 | 34.2 | 8.1 | 0.0 | 0.5 |
|  | B | 5.9 % | 20.8 | 34.2 | 31.2 | 7.6 | 0.0 | 0.2 |
| There are so many different recommendations about preventing cancer, it’s hard to know which ones to follow | A | 32.6 % | 38.0 | 13.6 | 8.0 | 7.5 | 0.0 | 0.3 |
|  | B | 33.9 % | 37.3 | 13.1 | 8.4 | 7.1 | 0.0 | 0.2 |

## Relative Frequency Distribution – Cumulative ‘Not Ascertained’ Responsecombines no opinion, don’t know, refused

|  |  | List A
(n = 3,204) | List B
(n = 3,165) |
| --- | --- | --- | --- |
| CK – 13 | 0 | 49% | 37% |
|  | 1 | 27% | 26% |
|  | 2 | 13% | 17% |
|  | 3 or more | 11% | 20% |
| CK - 14 | 0 | 80% | 81% |
|  | 1 | 14% | 13% |
|  | 2 or more | 6% | 6% |

## Logit Regression – Odds of ‘Not Ascertained’ Response for CK-13 Items – Summary of Results

- Regression included indicator variables for interview in English, complete interview, male, age, education, income, Hispanic, race, seek cancer information, others seek cancer information, ever had cancer, family ever had cancer
**List A**** –** (smoking, pesticides, fiber, stress, hit breast, family history, little exercise)
- Amount of variation explained by subject characteristics – range from 3% (hit breast) to 11% (family history)
- Significant predictors varied by topic; consistent, significant effects for Complete Interview (-), age (+ for groups < 45 years), education (+ for groups less than college degree), seek cancer information (-)
**List B**** –** (high fat diet, sun, few fruits, alcohol, many sex partners, race/ethnicity, pollution, radon)
- Amount of variation explained by subject characteristics – range from 3% (alcohol, radon, many partners) to 17% (exposure to sun)
- Significant predictors varied by topic; consistent, significant effects for education (+ for groups less than college degree), seek cancer information (-)

## Cumulative ‘Not Ascertained’ Response – Means for Selected Covariates

|  | List A |  | List B |  |
| --- | --- | --- | --- | --- |
| (significant differences shown in bold) | CK-13 | CK - 14 | CK - 13 | CK – 14 |
| Spanish Interview / English Interview | 1.30 / 0.92 | 0.67 / 0.26 | 1.75 / 1.37 | 0.47 / 0.25 |
| Partial Interview / Complete Interview | 1.43 / 0.93 | 0.47 / 0.28 | 1.74 / 1.38 | 0.45 / 0.26 |
| Female / Male | 1.01 / 0.84 | 0.27 / 0.30 | 1.48 / 1.26 | 0.26 / 0.27 |
| 18-34 years / 35 or older | 0.89 / 1.10 | 0.29 / 0.27 | 1.42 / 1.32 | 0.27 / 0.23 |
| Less than HS grad / HS grad or higher | 1.40 / 0.88 | 0.23 / 0.66 | 1.97 / 1.32 | 0.22 / 0.56 |
| Income under $25,000/ other | 1.14 / 0.87 | 0.21 / 0.48 | 1.65 / 1.30 | 0.20 / 0.45 |
| Not Hispanic / Hispanic | 0.92 / 1.17 | 0.25 / 0.53 | 1.36 / 1.62 | 0.25 / 0.37 |
| Not seek cancer info / Has sought cancer info | 1.10 / 0.77 | 0.40 / 0.15 | 1.63 / 1.14 | 0.39 / 0.13 |
| Never had cancer / Had had cancer | 0.95 / 0.94 | 0.29 / 0.27 | 1.37 / 1.55 | 0.27 / 0.24 |

## Regression Results – Cumulative ‘Not Ascertained’ for C-14 Series

|  | List A sample |  | List B sample |  |
| --- | --- | --- | --- | --- |
|  | B | s.e. (b) | B | s.e. (B) |
| English Interview | -.059 | .060 | .047 | .059 |
| Complete Interview | -.207 | .114 | -.227 | .108 |
| Male | .014 | .022 | .001 | .022 |
| 18 - 34 years old | -.081 | .026 | -.088 | .026 |
| 35 – 39 years old | -.115 | .037 | -.098 | .036 |
| 40 – 44 years old | -.065 | .036 | -.064 | .035 |
| Less than HS grad | .324 | .042 | .249 | .042 |
| HS grad | .130 | .030 | .115 | .029 |
| Some college | .034 | .029 | .029 | .028 |
| Under $25,000 | .129 | .027 | .137 | .027 |
| Over $75,000 | -.050 | .030 | -.074 | .029 |
| Hispanic | .147 | .043 | .040 | .042 |
| Non-Hispanic Black | .089 | .035 | .115 | .033 |
| Non-Hispanic Other | .149 | .052 | .070 | .047 |
| No race information | .130 | .098 | .061 | .090 |
| Ever seek cancer info | -.145 | .024 | -.168 | .023 |
| Other seek info  | -.039 | .030 | -.048 | .029 |
| Ever had cancer | .021 | .035 | -.010 | .033 |
| Family ever had  | -.032 | .023 | -.059 | .022 |
| constant | .514 | .125 | .488 | .121 |
| R2 | .12 |  | .10 |  |

## Conclusions

- Despite being asked to report ‘what they think’, many subjects said they had no opinion
- Probably because they were reluctant to volunteer that they ‘didn’t know’
- The lowest educated respondents and those who had not looked for cancer information were most likely to respond ‘no opinion, don’t know, or refused’ on both ‘knowledge’ (CK-13) and ‘belief’ (CK-14 questions

## Future Considerations

- New rounds of the HINTS should consider alternate question designs
- Yes, no, don’t know response options
- Uniform topic list (no split ballot)
- Question and response wording that makes clear distinction between opinion, knowledge recall, or estimation