“…Table 1 reveals that several cross-sectional studies documented a U shape using life satisfaction, the Cantril ladder, and happiness items (Beja, 2018; Cheng et al, 2015; Daroudi, Rashidian, Zeraati, Oliyaeemanesh, & Sari, 2016; Graham & Pozuelo, 2017; Grover & Helliwell, 2019; Lin, 2016; Ruseski, Humphreys, Hallman, Wicker, & Breuer, 2014; Schwandt, 2016), but others found mixed evidence. That is, the shape (and associated nadirs and peaks) of the age-happiness connection varied depending on the country and region of the world (Bauer, Levin, Boudet, Nie, & Sousa-Poza, 2017; Laaksonen, 2018; Morgan, Robinson, & Thompson, 2015; Steptoe et al, 2015), whether control variables such as education and marital status were included in the analyses (Blanchflower & Oswald, 2019; Ferrante, 2017; Hellevik, 2017), year or period of time when the surveys were administered (Kolosnitsyna, Khorkina, & Dorzhiev, 2017; Olaroiu, Alexa, & van den Heuvel, 2017), and gender (Kolosnitsyna et al, 2017; Laaksonen, 2018). Some studies found a U shape, but the low point was outside of the typical range of midlife (defined as 40–60 years of age; Freund & Ritter, 2009), for example, in the 30s (Laaksonen, 2018; Li, 2016) or up to age 70 (Kolosnitsyna et al, 2017).…”