The evolution of lambda(2), a parameter whose definition is recalled i
n the paper, has been used in order to test various intermittency mode
ls in turbulence. This paper aims to validate an experimental, model i
ndependent, method for extracting this parameter from the velocity dif
ference probability density functions (pdf). We also discuss the chara
cteristics of an experiment which could push further the analysis of t
hese pdf.