Today, happiness is typically measured using self-report surveys. Self-reporting is prone to cognitive biases and other sources of errors, such as peak–end rule. Studies show that memories of felt emotions can be inaccurate.[36] Affective forecasting research shows that people are poor predictors of their future emotions, including how happy they will be.[37]. Happiness economists are not overly concerned with philosophical and methodological issues and continue to use questionaries to measure average happiness of populations.
How to find out, what is happiness? The scientific thing to do is analyze its properties and origin and try the best possible explanation we can deduct from the facts.