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Partisan Bias and Policy Outcomes


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A recent analysis of budgetary changes reveals that when one party controls the House, Senate, and Presidency, its members make counterintuitive spending choices with surprising frequency.

Congressional gridlock over the federal spending bill in October and the resulting government shutdown that occurred in 2013 had significant negative impacts on the U.S. economy and cost the federal government billions of dollars. Congress’ inability to pass the bill arose from what Americans usually consider the conventional partisan divide over spending—Democrats wanted to increase funding and Republicans wants to make cuts. But when they do ultimately put together a budget and pass appropriations bills to fund the government, how will these two partisan goals be combined? Will the presence of divided government result in more large spending cuts than in years when Democrats alone controlled the budgetary process?

A recent analysis of U.S. budgetary changes by IPR political scientist Laurel Harbridge and Sarah Anderson of the University of California, Santa Barbara, sheds light on this question. It reveals that Democrats actually make larger spending cuts than Republicans do and that this occurs even when they have unified control of government. This puzzling pattern can be explained by what Harbridge and Anderson refer to as “motivated information processing.”

In a forthcoming article in American Politics Research, Harbridge and Anderson use their analysis of U.S. budgetary spending, including data from 1955–2002, to explore how and why party control, congressional turnover, and budgetary constraints affect spending, including the start or elimination of programs and year-to-year funding changes. The two argue that in an information-rich world, policymakers are bombarded with so much information they cannot process it all. In response, they fall prey to their partisan biases and engage in motivated reasoning. This leads to selectively ignoring information that runs counter to their partisan predispositions.

Laurel Harbridge
Laurel Habridge

When one party controls the House, Senate, and Presidency, this selective intake of information influences the policymaking process, leading Democrats to increase spending and Republicans to decrease spending. But, as a consequence, the party must later make corrections to balance their prior decisions.

“This is usually in response to an obvious signal from the world around them or to correct a series of partisan policies that have resulted in spending that is seen as too low or too high,” Harbridge said. “Partisanship manifests in intuitive ways, like Democratic control resulting in more increases to spending on various programs, but also in less obvious ways when policymakers need to make large corrections to their earlier party-driven choices.”

The co-authors found that motivated information processing caused the parties to make counterintuitive spending choices with surprising frequency after pursuing their partisan goals. When they needed to counteract prior increases in spending, Democrats often made large cuts to the budget. Harbridge and Anderson also observed that the effects of motivated information processing are strongest on issues closely aligned with the parties and during off-election years.

“The counterintuitive findings make sense when you realize that lawmakers are subject to bias just like the rest of us,” Harbridge explains. “When these partisan biases affect their ability to make decisions, they often translate into policy outcomes with significant consequences.”

Laurel Harbridge is assistant professor of political science and an IPR fellow.