What type of data collection involves large samples of households providing data over time?

The correct answer, which identifies the type of data collection that involves large samples of households providing data over time, is consumer panels. Consumer panels are structured groups of individuals whose behaviors, opinions, or experiences are monitored over a period. This method allows researchers to gather data on evolving consumer preferences and trends continually.

Consumer panels are particularly valuable for longitudinal studies as they provide insights into changes over time. A key aspect of this method is that it typically involves a significant number of households, which helps to ensure diversity and representativeness in the findings. Researchers gain access to rich data that can inform marketing strategies, product development, and consumer behavior analysis.

In contrast, focus groups involve small, diverse groups of participants discussing their perceptions and opinions, which are useful for qualitative insights rather than large-scale data collection. Case studies focus on deep dives into specific situations or entities rather than collecting data from large samples over time. Surveys allow researchers to collect information quickly from many respondents but do not necessarily involve the long-term commitment of individual households, which is characteristic of consumer panels.