The top political pundits are confidently declaring that the key to judging the Republican and Democratic presidential nominating contests will be the tally of delegates racked up by each candidate, but what the political analysts often omit is that those delegate counts can be wildly different depending on which news outlet one consults.

On the Republican side, CNN’s tally has Mitt Romney with 72 delegates, the Associated Press has that number at 59, and so far CBS has counted just 35 delegates for the former Massachusetts governor. Governor Huckabee has racked up 40 delegates according to the AP, 29 delegates per CNN, and only 7 in the view of CBS.

RELATED: A Chart of Delegate Counts by Four News Outlets

On the Democratic side, CNN has Senator Clinton leading Senator Obama of Illinois in terms of delegates, 210 to 123, but NBC’s “leaderboard” has Mr. Obama narrowly ahead, 38 to 36.

“The delegate counts are not really ‘counts.’ They’re really delegate estimates,” the director of surveys for CBS News, Kathy Frankovic, said yesterday. She said a key reason for the largest discrepancies is the different standards news organizations have about when to add delegates to the total.

“We are not accepting Republican delegates out of Iowa and Nevada. The AP is awarding them, but doing them on a formula we don’t understand,” Ms. Frankovic said. “The only votes that have been taken in those states is a nonbinding straw poll.”

Some state parties award their delegates strictly based on the popular vote, but not all do. That was illustrated last week in Nevada, where Mrs. Clinton won the popular vote by 5%, but most observers later concluded she had lost the projected delegate race there to Mr. Obama, 12 to 13.

Another large factor in the differing counts is that some news organizations sometimes choose not to tally the 850 Democratic superdelegates, many of whom are federal, state, and local officeholders and party officials. NBC’s tally on the MSNBC Web site does not include the superdelegates, which is why Mrs. Clinton, who has a lot of establishment support, seems to be lagging in that count. CNN’s main politics Web page also highlights a tally of delegates won in primaries and caucuses. One has to drill further into the site to see the numbers including superdelegates.

“I don’t understand why people haven’t allocated the superdelegates,” Ms. Frankovic said. “Certainly, they’ll be counted as much” as those selected state by state, she said. In addition to the Democratic superdelegates, there is a smaller number of unpledged Republican delegates, as well as delegates in both parties who are sometimes released when their candidates drop out.

The loyalties of many of these delegates can be ascertained from public endorsements, but not all can be sorted out that way.

“It’s very good to stay scientific as much as you can, but you’ve got to apply reporters’ intelligence,” a former political director at ABC News, Hal Bruno, said. “My hunch is everybody is so oriented to computers now that all they can do is crunch numbers. You’ve got to do the reporting. The reporting is as important as the number crunching.”

Ms. Frankovic declined to discuss how CBS assembles its tallies, except to say they do so “internally.” Spokesmen for the AP and NBC did not return messages seeking comment for this article. A CNN spokeswoman said those who oversee political coverage were busy preparing for last night’s Democratic debate.

Mr. Bruno, who headed ABC’s political shop for 19 years, said he used to hire a well-connected Democrat and a well-connected Republican for the presidential election year to work contacts in each state. “A lot of superdelegates say they’re uncommitted and it’s untrue,” he said, adding that reporting could usually establish at least that a delegate was leaning toward one candidate or another. The former journalist said he also checked in regularly with people the campaigns hired or assigned to tally delegates.

“The candidates that are losing will always try and spook you into thinking they’d got hidden strengths,” Mr. Bruno said, pointing in particular to an attempt by President Reagan’s campaign manager, John Sears, to claim a delegate edge over President Ford’s campaign in 1976.

Mr. Bruno said that at different times during the campaign season he produced separate tallies of “hatched,” “unhatched,” “leaning,” and “firm” delegates, though he acknowledged that the numbers were usually blended together before being broadcast.

“Until now, the presidential campaign is psychological warfare,” Mr. Bruno said. “You can win even though your guy lost and you can lose even though you’ve won….Starting with Florida, it’s a different game. The cold hard bloodless numbers take over and no matter what a candidate says or does, the only thing that counts from here on in is that delegate count.”

To win the Democratic nomination, the support of 2,025 delegates is required; for the Republican nomination, the magic number is 1,191 delegates.