Those who seek our votes like to promise they can bring manufacturing jobs back to America. Just cut taxes and put up a few trade barriers, they say, and watch the blue-collar jobs grow.

But it’s not that easy. Businesses that are trying to build a flexible global supply chain at the lowest cost don’t decide where to locate their production or distribution facilities based on taxes alone, or any other single factor. In some cases, high taxes may be a deal breaker. But they’re just one consideration of many, including proximity to the firm’s markets, availability of technology and the education level of the local work force.

Companies look at where their top suppliers are located, because having production facilities near their best suppliers can save money. They consider whether a less-educated work force can be trained easily enough to offset the expense of locating in a country with better-educated workers.

Even things like long-term currency depreciation or appreciation trends are important when companies decide where to build plants. In a recent simulation-based study, we discovered that under certain conditions, when a country’s currency depreciated as little as 10 percent for a significant period of time in relation to the U.S. dollar, some firms could be led to relocate their production to the more economically attractive country.

Politics play a major role, too. Country A may be less expensive than Country B, but if Country A is politically unstable, the company might incur costs that make politically stable Country B a better location.

And basic market forces are always important. If a U.S. company sells more of its product in China than in the United States, it’s cheaper for the company to locate its manufacturing facility in China. Not only is it closer to its primary market, but the firm also spends less money shipping small amounts of product from China to the United States than it would spend shipping large amounts the other way.

Firms with more flexible supply chains have the capability to minimize the costs of major disruptions because they can react more quickly to economic shifts or events such as natural disasters. The earthquake and tsunami in Japan provide a good example.

Toyota Motor Corp. had facilities in the area that was devastated by the disasters, and that could have caused lengthy and costly delays in the company’s global operations. But Toyota had such a flexible supply chain that it was able to shift production. The key is to develop a system that contains enough potential incremental capacity somewhere else to absorb unexpected shocks.

Though political leaders offer low taxes as a silver bullet to improve global competitiveness, a much more complex approach to public policy is needed for those improvements to become a reality.

Renato De Matta is a management sciences professor at the University of Iowa’s Henry B. Tippie College of Business.