BILOXI, Miss. – Anyone who’s ever received a free promotional t-shirt from a company or a political candidate understands that a one-size-fits-all approach seldom works.

Apart from the people in the broad middle, the standard-sized t-shirts hang to the floor on petite individuals and cut off blood circulation for larger ones.

One-size-fits-all doesn’t make sense in the fashion world – or any other world, really. Imagine how uncomfortable life would be if cars, homes or grocery products came in only one size.

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The average American understands that reality, but the labor unions that feed off of America’s public schools refuse to acknowledge it.

Case in point: The Mississippi teachers union is calling for “a blanket pay raise for the state’s (32,000) public school teachers,” regardless of how well they do their job, reports the Associated Press.

“We are going full throttle for an education pay raise this year,” said Joyce Helmick, president of the Mississippi Association of Educators.

It’s unclear how much of a pay raise the MAE thinks all teachers should receive, though the AP notes individual teachers are already receiving an annual (step) raise of $495, according to the terms of the state’s teacher salary schedule.

The union says the raises are needed because Mississippi teachers’ average salary ($41,646) is the second-lowest in the nation.

One Republican legislative leader estimates that a flat $1,000 raise for every teacher and certified school employee would cost at least $35 million. That’s money the state might not have right now, considering its Medicaid program and prison system are both expected to run deficits this year, the AP reports.

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Republican Gov. Phil Bryant agrees that teachers should be given raises, but only those who’ve proven they deserve one. Bryant “only wants to give pay raises based on merit,” as defined by student test scores and teacher evaluations, the AP reports.

Such proposals threaten the union’s premise that all teachers are interchangeable cogs in the public school “machine.” If all educators are equal, than they all deserve an equal raise.

That view is completely detached from the real world rules that most Americans operate under, but it holds a certain emotional appeal for a lot of folks. They think higher wages for all is the way to attract the “best and brightest” to the teaching profession.

But studies have shown that many outstanding young teachers leave the profession because they receive the same compensation as less qualified colleagues.

Before making any final decisions, Mississippi lawmakers should check out the market-based wage plans that leaders of Colorado’s Douglas County School District recently adopted.

Douglas County school officials correctly believe that educators in hard-to-fill subject areas (math, science, technology) deserve higher pay than teachers in low-demand subjects (gym, art, English). They also believe that teacher pay should be based on performance.

That’s the way to attract top talent to Mississippi schools, regardless of what the union may say.