Running up to 30 pages, this threat "matrix" has become part of President Bush's morning routine in the fight against terror.

Each day Bush is at the White House, Attorney General John Ashcroft, FBI Director Robert Mueller and CIA Director George Tenet brief the president in the Oval Office about threats facing the United States at home and abroad.

The crux of their briefings is the document formally titled "Terrorist Threats to U.S. Interests Worldwide," or more informally, the "Daily Threat Matrix."

The high level of threat "chatter" collected worldwide and detailed in the Matrix was a key to the Bush administration's decision Tuesday to raise the terror threat level from elevated (yellow) to high (orange). The other main consideration was recent deadly bombings in Saudi Arabia and Morocco that officials say point to a resurgence of activity by the al-Qaida network.

Officials say they expect the alert level to remain high at least through the Memorial Day weekend.

In recent congressional testimony, Mueller said the Matrix is produced "to ensure we are working off a common knowledge base" as officials assess threats from al-Qaida and other groups and "lone wolf" extremists and violent homegrown radicals.

The document is "a list of every threat directed at the United States in the past 24 hours," Mueller said.

Government officials familiar with the Matrix described it to the Associated Press as a daily compendium of a few pages to 30 or more. Each threat is entered in tabular format, with those considered the most severe listed first.

No threat is ignored, and even known hoaxes are reported, officials say.

Sometimes only pieces of the Matrix get out publicly, leading to a distorted view of reasons behind heightened vigilance for terror, officials say. Last week, some news reports focused on threats on Internet sites - never corroborated or specific - that attacks could be imminent in New York, Washington, Boston and the Eastern coastline.

Officials stressed the Matrix provides a cumulative snapshot that, taken together, gives officials a broad picture of the overall ebb and flow of threats.

Included in the Matrix is what government action has been taken to prevent or prepare for an attack. For the FBI, this action could mean getting an emergency warrant - Ashcroft sometimes is awakened in the middle of the night for his signature - to set up secret surveillance and tap telephones of suspected terrorists in the United States.

The Homeland Security Department might notify sensitive industrial sites about threats to their installations. The CIA could step up efforts to penetrate foreign groups that might be plotting.

Elements of the CIA-FBI "Daily Threat Matrix" used to determine the likelihood of a terrorist attack against U.S. interests:

- Type of intelligence source, such as human informant, phone interception, satellite imagery.

- Possible target or targets.

- Identity of group planning attack, if known.

- Method of potential attack, such as car bomb.

- Analysis about threat's credibility and context.

- Notes about actions taken, such as who was notified and what has been done.