> Even after the researchers controlled for previous performance and a range of demographic factors, soldiers who were the happiest and most optimistic went on

> Even after the researchers controlled for previous performance and a range of demographic factors, soldiers who were the happiest and most optimistic went on to earn significantly more job performance awards across the next five years compared with those who were initially unhappy and pessimistic. How does this study account for the scenario where people are happy because they are on a good career track and others are unhappy because they are not? For instance, someone who wanted to ace an entry exam for a new leadership position but failed to pass. Or someone who notices they lack certain core skills. Or someone who has life obligations or health issues that prevent him from making career progress? I suggest that if you have relative high certainty that you will be successful in the next few years you will be happier on average than when you already know that the following years will be shrouded in stagnation.