Attrition of sample members from a longitudinal survey can undermine the quality of the data and its research potential. especially when the sample members who drop out are different from those who do not. People who move house are more likely to drop out of the survey as they are harder to locate. and once located. https://www.roneverhart.com/1998-2006-TOYOTA-SIENNA-3-3L-Van-Lower-Engine-Oil-Pan-3MZFE-Engine-6-Cylinder-T/