Our paper questions the quality of electoral studies’ sampling design, focusing on age. We show that the oldest category of the actual electorate is often under-represented in such quota-based surveys. It’s crucial since those over 80 years old now account for 10% of French registered voters. The data reviewed comes from 5 electoral panels fielded between 2002 and 2012 and a barometer tracking opinions in 2012. The studies include between 4,000 and 40,000 respondents, enabling a refinement of age sub-categories. We also analyse how these representativity biases may affect the quality of the answers