Dale T. Mortensen, a Northwestern University professor who shared the 2010 Nobel Prize in economics for developing innovative methods to analyze unemployment and labor markets, died Jan. 9 at his home in Wilmette, Ill. He was 74.

His death was announced by Northwestern University in Evanston, Ill., where he had taught since 1965. He had lung cancer.

Early in his career, Dr. Mortensen became interested in two phenomena in the labor market that seemed to defy both common sense and the prevailing ideas of economics. He wanted to know why some people remained unemployed when businesses had jobs they could not fill, and he wondered why similar jobs could have significantly different salaries.

Dr. Mortensen shared the Nobel, and its $1.5 million in prize money, with two other economists, Peter Diamond of the Massachusetts Institute of Technology and Christopher Pissarides of the London School of Economics.

In the 1980s, they devised a method to study the dynamics of unemployment and the effects of government policies on the labor market. Their method became known as the DMP Model, for Diamond, Mortensen and Pissarides, and is widely used by scholars and government economists.

Dale Mortensen, Nobel Prize-winning economist from Northwestern University. (Lars Kruse)

In simple terms, Dr. Mortensen said when he won the Nobel Prize, his ideas revolved around this basic truth: “It takes time for workers to find jobs and for employers to find workers.”

In classic supply-and-demand economics, in which the market is allowed to operate with maximum efficiency and minimum governmental interference, the number of jobs and job seekers would be equal — a theoretical condition called a “perfect market.”

Similarly, according to a 19th-century concept called the “law of one price,” a commodity — whether a product or a salary — should have the same price wherever it was available.

Dr. Mortensen recognized that we do not live in a perfect world.

“Any sort of deviations from so-called ‘perfect markets’ — which is just an ideal, right? — is called a friction,” he explained to an interviewer from the Nobel committee in 2010. His goal was to account for these “frictions,” or inefficiencies in the marketplace.

Some economists and politicians have explained the differential by suggesting that generous unemployment benefits made people less likely to look for work. Dr. Mortensen found that even in a robust economy, some people are always unemployed, and some businesses have openings they cannot fill. For various reasons, the job seeker and the job never find each other.

To explain these missed opportunities, Dr. Mortensen became a principal designer of a practice called “search theory.” It has become a standard method by which economists attempt to describe various activities in which individuals search for something of value, whether a job, a house or a marriage partner.

Search theory is not a prescription for how an economic system should work, but rather a mathematical framework for analyzing how markets function.

“It’s just a way of viewing the world,” said Kenneth Burdett, a University of Pennsylvania professor who studied under Dr. Mortensen in the 1970s and worked with him on various projects.

In an ideal world, a perfect job, a perfect house or a perfect mate can always be found. But in the imperfect reality of our daily lives, Dr. Mortensen pointed out, knowledge is incomplete. Most people, whether searching for work or looking for love, are milling around with more hope than certainty.

A job-hunter may not be aware of an opening in another state or even around the corner. A marriage may seem to be made in heaven, but in economic terms it is dependent on a small matrimonial marketplace.

“I develop tools with which to think about those problems,” Dr. Mortensen explained to Bloomberg News in 2010. “I’m not a policymaker.”

He was not identified with any party or ideology, and his analytical framework has been used by people of differing political views.

“Dale was big on saying we must remember the human cost, the human reality of unemployment,” Burdett said. “He was a very concerned human being.”

Dale Thomas Mortensen was born Feb. 2, 1939, in Enterprise, Ore. He grew up in Oregon’s Hood River Valley, where his father worked in forestry.

He graduated from Willamette University in Salem, Ore., in 1961, and received a doctorate in economics from Carnegie-Mellon University in Pittsburgh in 1967.

Besides his long tenure at Northwestern, he was a visiting professor at many universities around the world, from Russia to Australia to Denmark to California. He published a book, “Wage Dispersion: Why Are Similar People Paid Differently?” in 2003.

Survivors include his wife of 50 years, religion scholar Beverly Patton Mortensen of Wilmette; three children, Karl P. Mortensen of Shelby Township, Mich., Lia DuBarry Mortensen of Chicago and Julie M. Glanville of St. Charles, Ill.; two brothers; and eight grandchildren.

After Dr. Mortensen accepted his Nobel Prize in Stockholm, he delivered a short, informal speech in which he quoted from Studs Terkel’s book “Working,” in which ordinary people described their livelihoods: “Work is about a search for daily meaning as well as daily bread.”