Multi-mode sampling

Multi-mode sampling is the process of accessing respondents using more than one mode for the same study. This could happen two ways: Different modes may be used only at the contact stage, while the sample itself remains on one mode - for example, contacting someone via e-mail to request that they do a study via phone or recruiting people via phone for an online or mail study.

Multi-mode may also apply to the questionnaire, where some portion of the sample answers online and another portion may answer via telephone. An advantage of keeping the study on a single mode is that this eliminates potential bias caused by mode effects.

Why is multi-mode important?

Today, 30% of the US population does not have Internet access (percentages vary by country). Older, less affluent, rural populations are less likely to be online. But conducting an entire study via phone, mail, or face-to-face could be cost prohibitive. Here, a multi-mode solution could be employed to conduct as much as possible online, then supplementing with phone or mail sample to fill in the population gaps. This approach is most commonly used in social science or government research where coverage is key. The US Census Bureau uses a multi-mode approach.