NEW YORK — If the pants fit, women will buy more of them, says Cricket Lee, the creator of a new fitting system that could make life easier for consumers.

Lee, chief executive officer of Fit Technologies of Dallas, demonstrated her new sizing system Sunday, on the opening day of the National Retail Federation's annual convention in New York. She hopes to have the system in 20 retail chains within the next 18 months, beginning this summer.

"Imagine if a woman could go into a dressing room and find pants that fit," Lee said. Based on research by the NPD Group of Port Washington, N.Y., Lee predicts that retailers will see sales rise by 25 percent if they use her system.

The Fit Logic system determines clothing size by measurements and body type, dividing women into three groups: top-heavy, hourglass and bottom heavy. The system assigns two numbers to each size, the first based on the tradition clothing size, the second designating body shape.

Actress Jennifer Lopez, for example, who wears a size 4, would be a size 4.3, meaning she carries more weight in her hips and thighs.

Retailers and manufacturers who buy the Fit Logic program will make their clothing to the program's fit specifications, which would be explained on hangtags.

Attempts to help women find the right fit aren't new to the apparel industry, but a universal fit system would give the industry something it hasn't had for decades. As it stands now, manufacturers use their own specifications for fit, and make the fit characteristics a part of their brand identity.

A woman who wears a size 12 by the standards used by Chico's, a chain that caters to baby boomers, measures 39.5 inches at the bust, 31.25 inches at the waist and 42 inches at the hip. At Ann Taylor, where customers skew a bit younger, the measurements for size 12 are 37-29-39.5.

"Women actually thought there was something wrong with them when they couldn't find clothes that fit," Lee said.

Manufacturers have tried to make it easier for customers by designating styles as "easy fit" or "classic fit," or by giving the fit categories names. Liz Claiborne, for example, uses names such as Audra to designate a fit type.

The problem with those efforts is that the size categories are different among the brands, Lee said.

David Wolfe, creative director for The Doneger Group, a New York consulting and buying business that serves retailers, applauded the Fit Logic initiative.

"The industry just has to get together and do this," Wolfe said.