What’s more worthless in trying to predict the outcome of the Republican primary: writing all the candidates’ names on scraps of paper and picking them blindfolded out of a hat or the Ames straw poll?

The smart money’s on the hat. For all the hoopla that surrounds the straw poll, scheduled to take place in Ames, Iowa, on Saturday, one could be forgiven for not knowing that it’s just the fifth ever held by the Republican Party — and its record of predicting, or even affecting, the outcome of the presidential race in that short history is beyond suspect.

A quick recap:

The first Ames straw poll in 1979 was won by George H.W. Bush, who also won the Iowa caucus; all of this was little more than a speed bump on Ronald Reagan’s road to the White House. The second one, in 1987, was won by the televangelist Pat Robertson, but the Iowa caucus that year was won by Bob Dole, while Mr. Bush ended up winning New Hampshire and ultimately the presidency.

The straw poll did better in the 1990s, if only by happenstance. In 1995, the eventual nominee, Mr. Dole, came in first — though he was tied with Phil Gramm, whose candidacy crashed and burned before the caucus came around. In 1999, George W. Bush won, but as the early national front-runner, he never faced any serious opposition.

So as we head into the first Ames straw poll of the 21st century, what can be gleaned from the festivities? Ultimately, it’s all a game of expectations. Can second- and third-tier candidates organize well enough to “beat expectations”? The motto: If you can’t make it here, you can’t make it anywhere.

So, here’s a compact guide for what to look for from each candidate, in rough order of poll ranking:

Mitt Romney: He’s expected to win (a loss would end his campaign). The number to watch is his margin of victory. Mr. Bush had a 10% margin of victory in 1999 over Steve Forbes. That’s also similar to Mr. Romney’s lead in various Iowa primary polls. Any margin smaller than that would be a surprise and a reason for concern for the Romney campaign.

Mayor Giuliani and Fred Thompson: Mr. Giuliani is the front-runner nationally; Mr. Thompson is in second place, despite not yet being an official candidate. Neither is participating in the straw poll, but their names will be on the ballot. Candidates who don’t participate tend to be punished, so either one can write off a bad showing as meaningless. But it will be of some interest to see who finishes above the other.

Mike Huckabee: Pundits often tout Mr. Huckabee as the candidate with the most potential to break into the top tier, but his poll numbers (even in Iowa, where he’s been campaigning hard) simply don’t show it. He said yesterday that if he’s not in the top half of the eleven-candidate field on the ballot, he’ll drop out. It’s hard to see how or why he continues, however, without a second- or third-place finish to put him in the pack with the Big Four.

Senator Brownback: This thinking man’s Rick Santorum is perhaps best positioned to make a surprise showing Saturday, tapping that Pat Robertson base. His Kansas-honed Christian right message has been front and center during the lead-up to Ames. Fliers for his effort promise “an afternoon of prayer and celebration.” He reportedly has almost as many buses coming as Mr. Romney. Perhaps the best indicator is the showing he made at the Conservative Political Action Conference back in March; in that organization’s straw poll, a strong on-theground effort netted him a third-place finish.

Senator McCain: He’s dropped as low as 3% support in recent polls. There’s no telling where the bottom is. The death watch continues.

Rep. Tom Tancredo: He hates immigrants. He will continue to hate immigrants.

John Cox and Duncan Hunter: Ever since Jim Gilmore dropped out of the Republican race, these two are in a heated competition for my coveted Who? Award.

Rep. Ron Paul: Mr. Paul’s online supporters have made Web-based polls of the Republican primary essentially meaningless, swarming sites like the Pajamas Media straw poll and giving their man a 2-to-1 margin of victory over his closest competitor. No scientific poll, however, has shown Mr. Paul registering better than 1% or 2%, and it’s unlikely they can adapt their cyber-tactics to the real world. Paulites are already calling voter fraud, but any low showing is likely to be legitimate.

Tommy Thompson: He’s said he will drop out if he doesn’t come in first or second. See ya!

Visit the Sun’s LatestPolitics.com on Saturday for coverage from Ames.