Should you ask directly? What rice farmers reveal in list experiments regarding improper disposal of agricultural waste

Improper disposal of agricultural waste is widespread globally, yet accurately measuring its prevalence is challenging because self-reported data are susceptible to social desirability bias. We conducted list experiments (LE) with 535 rice farmers in Nam Dinh province, Vietnam, to estimate the prevalence of three discouraged practices: rice straw burning; improper disposal of pesticide containers and leftover pesticide. Indirect questioning revealed that 69.2% of farmers burned rice straw, 40.3% improperly disposed of pesticide containers, while 61.7% improperly disposed of leftover pesticides. While list experiment estimates exceeded direct-question estimates for pesticide-related behaviors, the gap was only statistically significant for leftover pesticide disposal. A reporting gap of 21.6 percentage points indicate substantial underreporting of this specific practice. Our subsample analysis further indicated that the number of cultivated lands parcels were negatively associated with improper container disposal and male respondents underreported improper container disposal. Respondents of both genders underreported improper disposal of leftover pesticides, although the extent of underreporting did not statistically differ by gender. We found no evidence of misreporting for rice straw burning; however, this practice was significantly more prevalent among female farmers than among male farmers. These findings demonstrate the value of list experiments for measuring sensitive agricultural waste management behaviors. It also suggest that monitoring and intervention strategies should account for substantial underreporting of improper pesticide waste disposal.