Strengths Finder 2.0 is an online personality test disguised as a book. The test administrators charge you to take their test. To make the idea of spending $25 to take a personality test palatable, they throw in a hardcover book.
The schtick is: this test finds your strengths. According to the authors, other personality tests point out where you are on some scale: e.g., extrovert vs introvert. The authors decided to instead focus on strengths; glad-handing or sulking for extroverts and introverts. (Ha. I kid. Oh jeez, did I just rile up people at either end of that personality scale? Moving right along...) Why do they take this approach?
The authors say that other personality tests focus on people's weaknesses.
Huh?
There are a bunch of personality tests out there. You might have heard of Meyers-Briggs, those folks who can describe you with a four-letter word acronym. There are others: True Colors, OCEAN/Big5, What Harry Potter Character are you Most Like? I've taken a bunch of these. None of them focused on my shortcomings... well, I was kind of disappointed to find out that I'm not similar to Hermione Granger, but let's not dwell on that.
Maybe the authors of Strengths Finder think that people focus on the negatives because... well, I think that the authors are psychologists. Don't psychologists study pathological psychology a lot? They probably are used to other personality tests... the Autism-Spectrum quotient, the the NEO PI-R, the "Could I possibly be an Axe Murderer?" quiz.
But most folks don't do that. Most folks' encounters with personality tests are these pop-psych.... ahem. So.
So... as near as I can tell, this test's gimmick is based on a shaky premise.
There are some folks who I wish would read this book. Those are: people who have recently tried their first personality test and who have ascribed great significance to the results. You may have met these people. They are very excited. They have just found out that they are INTJ and what that means, and their places on the axes of personality. They have learned that people are different. They will talk your ear off about it. They can be very tiresome.
A good cure for this is: point them at another personality test. (I kinda like OCEAN/Big5, but I'm not sure that the choice of test matters much.) Just get them to take a second personality test. They take the test. It gives them a similar answer—but in a different way. One test plots your personality on a range between the extremes of Judging vs Perceiving. Another test figures out where you are between Compassion and Outspokenness. Apparently, there's more than one way to draw lines through the vector space of personalities.
Once folks figure out the arbitrary nature of how each measurement slices up the personality space, they calm down a bit.
And they've still learned the important thing: People are different. If you approach someone one way and it goes well, don't assume that the same approach will work well with someone else. It's worth it to learn to watch for people's reactions... because you can't assume that they'll all react the same way to stuff.