Every year, NRC conducts hundreds of surveys across the U.S. but only rarely can our findings be put to the test. After all, who is to say that a survey is correct when results show 80% of residents admire the police? So we like to look for instances where our findings can be compared to big national studies to see how close we came to those expensive institutional findings.
We had such an opportunity during our work on a survey with the Colorado Department of Transportation (CDOT). To weight survey results, we collected demographic and household information about respondents. As a further step, we compared our demographic findings with those from the Center for Disease Control’s National Health Interview Survey (NHIS). The results from NRC’s survey were extremely close to those of the NHIS. The NHIS found that of respondents, 43% said they use a cell phone; only, 51% use a landline and cell phone and 7% use a landline only; of the respondents to NRC’s survey, 41% said they use a cell phone only; 53% use a landline and cell phone; and 6% use a landline only.
| Cell Only | Landline and Cell | Landline Only | |
| CDOT Report | 41% | 53% | 6% |
| NHIS | 43% | 51% | 7% |
All in all, there was a difference of only one or two percentage points in each category. Tests of the validity of NRC survey work reinforce the robustness of our methods. Through our rigorous and scientific sampling, we can achieve a level of clarity and accuracy comparable to much more expensive surveys with less time and money. Rigorous methods benefit everyone by yielding accurate results and transparency of findings and methods permit tests of validity like this one that enhance the credibility of survey projects.