Let me be clear: When it comes to the reshoring debate, I’m an agnostic. I believe in numbers. And while not everything in business can be perfectly quantified, numbers help separate emotion and impulse from fact.

Evidence is mounting from surveys and direct statements by leading manufacturers, such as GE (IW 500/5) and Ford (IW 1000/6), that the flow of U.S. production overseas is leveling off and that domestic production is on the rise. There is a lot of emotion being generated about this, as there was when companies departed our shores. There is also some mystery and uncertainty about why this trend is actually happening and if it can be sustained.

Manufacturers are reinvesting here to more efficiently serve the world’s largest free market. That’s why they are back. They are not returning on an impulse or because of public pressure. But unlike when they left, this time they are measuring why they should return.

I can say with confidence that most manufacturing companies that left the U.S.—with a goal to ship products back—didn’t do much offshore accounting. They based their decisions largely on favorable piece-part costs (from low-detail bids) and on cheap, unburdened foreign-labor rates.

What they encountered offshore was an indirect labor burden of five-to-one; constant turnover, training costs and wage hikes; escalating shipping fees—and an impaired asset base back home.

Travel and other expenses were hidden in corporate budgets and were never placed on the piece part that first drew them to foreign soil.

Once their overheads started to skyrocket and operating profits plunged, however, those companies felt the “real” math like a stomach virus.

The lesson: even if you choose not to practice Total Cost of Ownership (TCO), your company will live or die by it anyway. So better do TCO with the joy of playing a favorite board game, or watch your profits tumble and competitors step ahead.

How do we measure the right things now and create a sustainable path? If your company is still silo based with design and procurement on opposite ends, then freely available TCO spreadsheet approaches, such as those championed by Harry Moser from the Reshoring Initiative, will allow you to be directionally correct in more of your forward assumptions. Then the next step is to build an integrated team that drills down into key operational data and can periodically refine and refresh the analysis.