Furthermore, ticket prices have also risen sharply in Canada and Europe since the mid-1990's, suggesting that deregulation of radio in the United States is not driving the trend.

It is certainly possible that Clear Channel uses its muscle to sign up concerts for national or international tours, but one would have expected the regional data to leave some trace of Clear Channel's influence if it was the main force behind accelerating prices.

Another problem is that Clear Channel is losing money on concerts. The company blames artists for demanding higher fees, which it says cause higher ticket prices. Although paying higher fees may reflect predatory behavior intended to drive out competitors, it is nonetheless surprising that Clear Channel has not managed to profit from concerts in areas where it dominates the radio market.

So what does explain the surge in ticket prices?

One possibility is that the cost to the consumer has not actually increased because scalped tickets render the list price irrelevant. The rapid growth in list prices, especially for the best seats, could have merely displaced scalpers. That seems unlikely, however, because declining ticket sales suggest that costs are rising. Fewer concerts sell out, and prices have surged even for those that sell fewer than 90 percent of their tickets.

Furthermore, the extent of scalping is often overrated. To check, I conducted a survey of 858 fans when Bruce Springsteen and the E Street Band performed at the First Union Center in Philadelphia this month. The concert was a throwback: every ticket in the house sold for $75, well below the market rate. Yet only 27 percent of the tickets were bought through a scalper or ticket broker, or over the Web. The average ticket that was resold went for around $280, yet most fans paid the list price. The list price is indeed relevant.

Mr. Springsteen deliberately set the price at $75 for his entire tour to give value to his fans — and succeeded. If the market price for a ticket was $280, Mr. Springsteen gave almost $3 million of extra "consumer surplus" to his fans in Philadelphia, double the ticket revenue the concert actually took in.

So why the surge in ticket prices?

I suspect the main reason is that the growing ability of fans to download music free from the Web — legally or illegally — has cut into artists' revenues. Millions of people have downloaded music from Napster, Morpheus and KaZaA — and bought fewer records as a result. Music sales are plummeting, putting downward pressure on artists' royalties.