Houllier, a former French national team coach, said analysis of the first round showed several other trends. Many more goals were being scored following corners, midfielders were catching up with strikers as goalscorers and there was a sharp drop in the number of goals from outside the penalty area compared with the 1994 tournament.
Houllier, who described Christian Vieri as the best striker so far, said the Italian's goal against Norway from a long through ball was a classic example of how the tackle from behind rule was helping the game.
"Before, Vieri would probably have been brought down before he could shoot," he said. "Now defenders know they will get a red card if they tackle from behind so they have to lay off. This is positive for the game."
Accompanying Houllier on Fifa's panel of experts are the former national coaches Rinus Michels, of the Netherlands, Oscar Washington Tabarez, of Uruguay, and Joseph Venglos, of Slovakia.
Analysing the 126 goals scored in 48 matches Houllier said 17 goals had been scored following corners, compared with just four at the same stage four years ago. Goals from outside the area accounted for only 10.3 per cent of those scored whereas four years ago there were almost twice as many.
Strikers scored 52.4 per cent of the goals, (down from 65.6 per cent) while the midfielders' share rose from 25.8 per cent to 37.3 per cent.
Houllier said their analyses showed that players' technical standards had risen appreciably since 1994 as had their athletic prowess. He said most teams played a 3-5-2 formation and that the main change from four years ago was that only Scotland used the tactic of "pressing" the opposition.
Teams now preferred to funnel back and defend en masse, he added. The quick through ball was one of the favoured tactics being used to break down such defences.
Many teams were using a libero in front of their defence, often an important player who acted as team leader. He cited Argentina's Matias Almeyda, Brazil's Dunga and France's Didier Deschamps.
Houllier said the players who had most impressed him so far were Vieri, the Argentina midfielder Ariel Ortega and the French defender Marcel Desailly. In goal he said he preferred Paraguay's Jose Luis Chilavert and Gianluca Pagliuca, of Italy.Reuse content