Math teacher Edwyn Claude plunges through the halls of one of Miami-Dade County's most crowded middle schools with his classroom stuffed into a 30-pound suitcase. Again and again, he sets up in borrowed rooms.

"If I had a classroom, I'd decorate it the way I'd like, green, because it kind of keeps the kids awake and it's psychologically proven, " said Claude, a first-year teacher at John F. Kennedy Middle. "And anyone could walk in and know that they're in a math class." But there is no classroom for Claude. Fifteen years after Miami-Dade Public Schools launched what was then the nation's biggest school construction campaign, a crowding crisis worse than ever chokes the district.

The district built 54 regular elementary, middle and high schools since 1988, but most opened with dozens and sometimes hundreds more students than seats, sending administrators on a scramble for space, teachers and supplies.

And at older schools such as Kennedy Middle, at 1075 NE 167th St., the gap between students and seats has grown dramatically worse.

Yet, it happened when the School Board had billions of dollars to spend.

In 1988, the board promised to "meet essentially all of its new construction" needs over five years with the passage of a bond referendum worth $980 million.

The district has actually received almost $6 billion since then through a combination of bond money, tax dollars and other sources.

But the district's campuses are still among the most packed in the nation.

Twenty-two percent of public schools in the United States wrestle with crowding. In Miami-Dade County, the nation's fourth-largest district, it's 66 percent.

No school district can control how fast communities grow, but a Herald investigation found that questionable policies and costly miscalculations helped fuel the crisis.

Consider:
* Since 1988, the school district spent just one-fifth of the $6 billion on new school construction. Thirteen percent was funnelled into major school additions and renovations, but some of those projects added extras such as administrative offices, not classrooms. Critics say the district should have sunk more money into space for students.

* In a county that grew by more than 92,000 students and is chronically short on land, the School Board opted to build schools smaller than needed. The board wagered that population shifts years from now would ease crowding, leaving behind a fleet of smaller, more suitable schools. But that decision relegated a generation of students to packed campuses.

Of more than 30 new elementary schools built for 885 students each, all but about 10 opened overcrowded.

* The district largely failed to track enrollment patterns that would gauge where new schools were needed most, and how many students would show up when they opened. The board in the mid-1990s dismantled the planning office that analyzed growth.

Though the district built a majority of new schools in high-growth areas, at least nine opened in areas that grew far less quickly or had no growth at all. New schools, meanwhile, were often overwhelmed by unexpected surges in students. * The district's building cycle is painfully slow. Crucial projects languished an average of 888 days before contractors were ever hired to start construction, often because of architect disputes or repeated planning changes. And even after contractors were hired, delays postponed some projects by months or even years.