(To see what a better problem solving strategy would look like, skip to the bottom... )
Many problem solving strategies in math are problematic in themselves.  Here are some typical problems with them:
(1) Some are too high level or abstract,
 and thus provide little to no traction for students to get into 
practically solving problems. Students either don't know what exactly 
they should do, or they misunderstand the intent of a step in the 
strategy.
e.g. one strategy calls for the student to describe any "barriers
 or constraints that may be preventing them from achieving their goal". 
 Would "the teacher hasn't taught us" be a valid barrier?  (The answer 
could be "yes", by the way.)
(2) It assumes a pretty smart student,
 rather than assume a barely passing one.  So the strategy works great 
for students who would've done fine without your help in the first 
place.
e.g.
 look at the above example again, and specifically that step calling on 
the student to describe any barriers: if a student was knowledgeable and
 cognizant enough to correctly and accurately identify the mathematical 
barrier to their solving a math problem, one could imagine that that 
particular student probably doesn't need much in being taught a 
simplified problem solving strategy anyway.
As another example, I like how many strategies, like this one,
 call on students to make a "plan to solve the problem".  If a student 
could make a usable and useful plan to solve a problem, then that 
student probably doesn't need your strategy!
On the other hand, some of them
 only mean for the student to plan on a technique to use, which is 
okay.  But "planning" is much too committal for techniques that may fail
 to work: that step should've been called, "try these and other 
techniques until you succeed".
 
(3) Some are too low level or narrowly focused,
 and thus provide little in framework to help students get from starting
 to solve a problem to closing out with a solution.  It turns out they're more like techniques rather than strategies.
e.g. another site
 calls using "Logical Reasoning" a strategy.  Certainly, students should
 use logical reasoning at some point, but what, specifically, should the
 student do in terms of logical reasoning?  What specific steps should a
 student follow if they use this strategy?
By the way, in most real problem solving situations, logical reasoning should not
 be used all the time anyway: often, a dose of creative, non-linear, 
lateral, thinking outside the cuboid, is necessary.  Thus, "logical 
reasoning" as a strategy is both too narrow in focus and too vague at 
the same time!
The
 same can be said of another strategy on that web site: "Guess and 
Check".  Can I just not even read the problem, and like just guess out 
of the blue then check?  Certainly all these strategies need to be 
taught well and used right, but even then, there's actually only a very 
narrow use-case for "Guess and Check", and so it can hardly be called a strategy.  Most of what's listed on that web site are more like techniques.
(4) Many are targeted towards a younger audience, and doesn't much help high school students learning algebraic solutions to solving problems.
Those examples of strategies above aren't bad or wrong; they are valuable to teach and learn in specific circumstances to particular students who needs it, and especially if none of them are singularly overly relied upon.  So long as students know those are rules of thumb that may or may not help, then it's okay, because they're problematic if taken too seriously as THE problem solving strategy to always use.
A better problem solving strategy
So any problem solving strategy that's worth teaching to students as a singular go-to overarching framework should:
- be useful to any student: both the best and worse student in math class should benefit
- grows with the student: the student could use it in grade 12 calculus as in grade 7 math
-  be broadly applicable and usable, whether with geometry, factoring, or in graphing 4th degree polynomials
- have specific steps to follow: it can't just be general aphorism to plan, decide, and act
- have general enough steps to follow so it's rightly a strategy or framework to solving a problem, not just a bag of techniques to try: it has to bring a student from the beginning to the end of solving a problem
This is a tough set of constraints, and I have yet to see a simple problem solving strategy satisfy all of these requirements.  But maybe there's one that works... (to be continued soon).
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