Telescoping errors occur if survey respondents misdate consumption or expenditure episodes by including events from outside the reference period in their recall. Concern about telescoping influenced the design of early Living Standards Measurement Study (LSMS) surveys, which used a two-visit interview format to allow a bounded recall. This design fell out of favor although not for evidence-based reasons. Recent guidelines to harmonize food data collection in low- and middle-income countries by using one-week recall increase the relevance of telescoping because errors spread over a shorter period will loom larger. To provide evidence on telescoping, we conducted a survey experiment in Ethiopia, randomly assigning a balanced sample – either a two-visit bounded recall or a single visit unbounded recall. The average value of reported food consumption is 16 percent higher in the unbounded single visit recall relative to the two-visit bounded recall. Put differently, in this experiment, telescoping errors amount, on average, to an entire extra day worth of consumption being included in the report for the last seven days. Most of the error is explained by difference in reporting of spending on less frequently consumed, protein-rich foods, so apparent diet diversity and dietary quality indicators are likely to be overstated when using unbounded recall. Read more.
