Claims about having found the truth on happiness advice is overdone considering the existing data

From Diminishing Effectiveness of Happiness Interventions: Positive Psychology

Stumbles on the Dodo Verdict by Ad Bergsma.  I have been deeply skeptical of the rigor and validity of most happiness research in the past couple of decades.  Even more than is usual for the social sciences, it seemed that the desire for a particular finding was determining the structure and the nature of the research, rather than the dispassionate pursuit of truth.

Even more than most, the whole field of happiness research seemed plagued by definitional inexactitude - failing to distinguish pleasure from joy from happiness from contentment from satisfaction.  

The conclusion is:

Citizens may choose to be inspired by the new science of positive psychology, just as I am personally and professionally indebted to the excellent work of Lyubomirsky, but it goes against the spirit of the founding fathers to suggest that somebody is unwise if he or she makes important life decisions without consulting the evidence base of positive psychology. Claims about having found the truth on happiness advice is overdone considering the existing data.

But the Discussion is more interesting and illuminating:

Two claims have been central in the marketing of positive psychology interventions and their role in the pursuit of happiness. The first selling point that the intentional pursuit of happiness is made easy thanks to scientific studies is overdone, which is recognized by experts such as Lyubomirksy. The second marketing idea is that positive psychology offers a vast improvement in happiness advice, thanks to the scientific rigor and quantitative research designs. This claim has not received empirical support, and there even is an indication of a decline in the effectiveness of following happiness training over time. This negative trend can probably not be explained by deteriorating quality of the intervention used in the pursuit of happiness. The happiness interventions used for scientific evaluations have not changed much. In the multiple positive psychology techniques studied by Hendriks et al. or the studies included in several meta-analysis [14,16,28], I can find no example of ‘faulty theories of happiness’ or ‘unprofitable approaches to become happier’. 
 
This possible trend of declining effectiveness of happiness training interventions is difficult to reconcile with the promise that more happiness studies will improve the quality and effectiveness  of happiness advice. Knowledge about positive psychology

interventions is important for basic hygiene of the field, and its baseline effectiveness, but it is a unethical to sell the opinions of even the best experts as the ultimate answer to the questions life poses us [76]. Or to borrow the words of Alexandrova [77]  for a different context: The lavish praise of positive psychologists for themselves violates ‘the main assumption of the subjective approach – that when judging happiness, the authority of how to weigh different aspects of our lives and experiences belongs to the subject’. Perhaps it is too early to tell, but it seems that positive psychology has stumbled upon the dodo verdict. Pursuing happiness is not a tame problem, for which a definitive answer about the best way to pursue happiness can be found, but a wicked problem, without definitive answers [78].

  
Miller et al. [25] suggest a way to proceed: we should focus less on what works, and more on how the pursuit of happiness works for whom. This implies that positive psychologists should keep Rogers’ non-directive imperative in mind. Positive psychologists can teach people to acquire new skills to combat the hedonic adaptation and negativity biases, but the experts should also give people room to connect with the things they already experience and know, so they can use the wisdom that is already built into the basic structure of their brains. The pursuit of happiness should be just as much about following the directive of the basic structures of our brains - doing more of what feels good and avoiding pain - as about correcting the way we perceive ourselves and the world. The expert should encourage clients to develop a personal philosophy of life.

 
The founding fathers of America came up with the following sentence in their declaration of independence: ‘We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.’  They were probably not vague, but left it deliberately open to each individual to pursue happiness in a way that suited them best. History has proved them right. Freedom turns out to be an important predictor of the happiness of citizens, and there are as yet no indications that freedom has passed its maximum in the freest countries [79].