“The gold standard for measuring psychological wellbeing is the Experience Sampling Method”

OECD (2013). OECD guidelines on measuring subjective well- being.
OECD Publishing. 

“An exclusive focus on retrospective evaluations
is untenable”
Nobel Laureate Daniel Kahneman & Jason Riis
Kahneman, D. & Riis, J. (2005). Living, and thinking about it: two perspectives on life. In F. A. Hupper, N. Baylis, & B. Keverne (Eds.), The Science of Well-being (pp. 285-304).
Oxford University Press.