(MONEY Magazine) – According to conventional wisdom, you shouldn't leave your current job for a new one unless it offers at least a 15% salary increase. But when the job requires that you move to another city, you need to also focus on another factor: the new town's cost of living. After all, your 15% raise will vanish if local costs are even 20% higher than where you live now. Fortunately, you can make such comparisons easily by using data from the cost-of-living index compiled by the American Chamber of Commerce Researchers Association (ACCRA). MONEY uses that data in our annual Best Places ranking.

ACCRA's composite index figure for any given city is an estimate of the cost of living in that particular U.S. metropolitan area. You can generally get the number by calling a city's chamber of commerce or asking your local library for the latest quarterly ACCRA study. To receive the full 60-plus-page report, you'll need to send $60 to ACCRA (4232 King St., Alexandria, Va. 22302). Below, I've noted ACCRA's cost-of-living composite indices for 30 of the country's largest metro areas. As you'll see, there's quite a disparity. New York City's index (219.7) is more than twice the U.S. average of 100, while Knoxville's affordable 88.6 means that the Tennessee city (ranked No. 160 overall by MONEY) offers a cost of living that's 12% below the U.S. average.

Before accepting a job offer requiring relocation, adjust the salary offer for the cost of living by comparing your present city's composite index against the index for the other city. Let's assume you live in Indianapolis, make $50,000 a year and have just received a job offer of $60,000 (a 20% increase). The one catch: You have to move to New York City. Should you take it? Follow my three-step procedure to see:

Step one: Subtract the composite cost-of-living index of your current city (Indianapolis) from the index of the destination city (New York), and then divide by your current city's index.

(Relocation city's index - Current city's index) [divided by] Current city's index =

(219.7 - 93.8) [divided by] 93.8 =

125.9 [divided by] 93.8 = 1.34

Step two: Take the value obtained in step one and multiply it by your current salary to see how much you'd need to earn in your new city to maintain your current standard of living:

1.34 X $50,000 = $67,000

Thus you would need to increase your salary by $17,000 just to maintain your current standard of living.

Step three: Now take the cost-of-living-adjusted salary from step two and add 15% (the pay boost you'd like to get before switching jobs):

$67,000 + $10,050 = $77,050

If the adjusted salary figure in step three is the same or more than the new salary offer, take the new job. However, if the offer is less (as it is here--$77,050 vs. $60,000), you may want to reconsider or try to negotiate for more money. Otherwise, your paycheck will inflate, but your standard of living will deflate.

--Jon Weimer, professor of business, Baker College

The cost-of-living index in 30 U.S. metro areas

New York City 219.7 Honolulu 177.4 San Francisco 172.0 Boston 138.9 Philadelphia 127.4 Los Angeles 116.7 Detroit 115.9 Santa Fe 110.8 Miami 109.3 Portland, Ore. 107.7 Denver 103.9 Washington, D.C. 103.8 Las Vegas 102.0 Phoenix/Mesa 101.4 Boise, Idaho 101.3 Minneapolis/St. Paul 100.9 Raleigh/Durham, N.C. 100.3 Atlanta 99.2 Baltimore 99.1 Provo/Orem, Utah 99.1 Cincinnati 98.9 Kansas City, Mo. 95.5 Des Moines 95.4 Austin 95.0 New Orleans 94.8 Sioux Falls, S.D. 94.8 Indianapolis 93.8 Louisville 92.8 Oklahoma City 92.3 Knoxville 88.6

Source: ACCRA Cost of Living Index Report, Fourth Quarter 1995 (Vol. 28, No. 4)