IF YOU'RE AMONG the 15 million visitors to the Philadelphia area's arts and cultural events each year, or the 43,000 paid and volunteer workers who make them happen, you owe a special debt of thanks to Peggy Amsterdam.

Amsterdam, 60, who died of cancer on Saturday, was an irrepressible advocate for arts and cultural organizations in this region - mammoth and small, famous and almost unknown.

As president of the Greater Philadelphia Cultural Alliance, an umbrella organization of more than 375 nonprofit arts and cultural groups, Amsterdam understood that they could not depend on anecdotes and goodwill to generate support. She helped establish programs to collect hard data to demonstrate how the arts not only bring together disparate parts of the community, but also make a critical contribution to the regional economy.

In 2004, Amsterdam was a founding member of the Cultural Data Project, a computerized research program funded by several foundations, including the Pew Charitable Trusts. The project gathers and sorts data from various arts organizations in the region, allowing them to compare themselves to similar groups, aiding in their ability to plan and apply for grants.

In addition, the data was used to produce Portfolio 2006 and 2008, two comprehensive portraits of arts and cultural activity in the Philadelphia region that illustrated the power of the arts as an engine for economic growth - as well as its fragility, since 40 percent of the organizations operate at a deficit. From its pilot here, the data project has been adopted by several other states and cities around the country.

AMSTERDAM'S most recent success was typical of her fierce commitment to the arts. After a three-month state-budget impasse, Gov. Rendell and the Pennsylvania legislature decided in October to fill a hole in the budget by taxing tickets to arts and cultural events while leaving sports events alone - that is, until Amsterdam led a statewide effort to kill the measure.

If arts and culture are the soul of a city, Peggy Amsterdam guarded and nourished Philadelphia's like few others.