The 'Listening to Latin America and the Caribbean' ('Listening to LAC' or 'L2L') project was motivated by the financial crisis of 2008, when policy makers in the region asked the World Bank how the crisis would affect their efforts to reduce poverty and what policy responses they could design to mitigate those impacts. Unfortunately, little data existed to answer this question, as poverty data is collected infrequently. The L2L project aimed to answer this key question: Can we use cellular phone communication technology to reduce the time and cost of collecting household survey data from a probabilistic sample without compromising data quality? This paper presents the results of two pilots of this mode of data collection in Peru and Honduras that allowed us to test this question empirically. The results suggest that using mobile phones for short and frequent surveys can produce high-quality data more quickly – and more cheaply on a per survey basis – than traditional methods, and can be a valuable complement to less frequent, more comprehensive, more expensive household surveys. But, in order for mobile data to produce timely information for policy decisions, the system for mobile surveys must be in place before the crisis starts. In other words, the L2L model cannot be launched after the onset of a crisis. This is because: (i) in order to ensure statistical representativeness, an appropriate sample must be drawn; (ii) it takes some time to recruit the panel; and (iii) an initial face-to-face interview is needed to collect data on the socio-economic characteristics of each household, which cannot be done by mobile phones due to the large number of questions. In addition, several implementation issues explained in this report need to be addressed ahead of time. For this reason it is not possible to initiate the program of data collection immediately after the onset of a crisis and obtain relevant data quickly. Therefore, the most desirable use of the L2L model of mobile surveys may be as a complement to on-going national surveys which collect mobile phone numbers of household members.