Whenever you write and publish a list of promising GOP candidates, you can be sure much of the next day will be spent reading passionate and lengthy explanations about how you inconceivably overlooked . . . everyone who you didn’t put on the list.

I often get told to take a look, or please mention, a little-known candidate here or there. I try to examine as many as I can, but before I say to NRO readers, “Check out this guy, he may surprise us,” I like to see some metrics, some tangible evidence that the campaign amounts to more than just a well-meaning guy with some loyal friends. Polls are great, obviously, and can help us know whether the incumbent is vulnerable, if the electorate is restless, and how much of a name-ID disadvantage the challenger faces. Fundraising is a useful metric, particularly the number of donors and the ability to build up cash-on-hand. (If you spend cash almost as fast as you take it in, your task is complicated.) If you tell me the candidate is drawing big crowds or you see a lot of yard signs, that’s terrific, but keep in mind those perceptions are often in the mind of the beholder. Bringing 100 people to a rally is nice, but remember that House races often include 200,000 to 300,000 votes.

A volunteer for a GOP longshot recently asked what I thought of the district and how I would go about beating a long-entrenched incumbent. I noted that the challenger had the joy of low expectations and the freedom to try something different or off-the-wall, with really nothing to lose. If the candidate wants to try to attract attention by skydiving with a banner, let him. It’s not like the stunt is going to cost him the lead. Worst-case scenario, it generates some horrific headline puns about plummeting momentum. (Okay, I guess technically the worst-case scenario is the parachute not opening.)

I told this volunteer that first-time candidates sometimes have to see their first campaign as a learning experience, figuring out what works and what doesn’t, what the candidate does well and what he doesn’t. If this new challenger attracts a higher percentage than any preceding Republican against this incumbent — roughly a third of the electorate — he’ll definitely get noticed by the state party and generate interest in another run in the near future; if they get within ten percentage points everyone in the state will be asking how they did it.

Anyway, a couple of questions . . .

El Segundo, California: “What do you think about Star Parker’s chances in CA 37? I was hoping she would make your baker’s dozen today. District is tough, but she is a great candidate and Laura Richardson is a weak incumbent with a penchant for foreclosures.”

The weaknesses of the incumbent are evident, but to say this is a tough district is an understatement: D+26. Obama won 80 percent of the vote here.

Elsewhere in California: “Forest Baker is running a grass-roots campaign against LONG-time incumbent Fortney‘Pete’ Stark for California’s 13th Congressional district. If you haven’t heard the name Forest Baker yet, it’s probably because here in California only two of our 53 Congressional races are considered in play. The 13th district is not one of them. The Republicans, Democrats, and media consider Stark a shoo-in to win back the seat. Many of us here in the district — which includes Alameda, San Leandro, Hayward, and Fremont — believe that Baker has a serious shot at defeating Stark. Stark is being scrutinized closer than ever, and as he approaches his 80th birthday many (Democrats included) are looking for new blood to represent them in Washington.”

I could see a challenger gaining traction on the basic message that it’s time for a change, and that Stark has gotten too long in the tooth (and careless in his mouth) to be of use to the district. But again, this is a supremely tough district: D+22; Obama won 74 percent of the vote and Stark hasn’t won less than 65 percent of the vote since 1992.

Up in Massachusetts: “What about MA 5th? Not even in play? Nikki Tsongas????? Look at the breakdown of Scott Brown votes……..I know we don’t have anyone just yet….but….this is one of the most conservative districts in Massachusetts. My bike riding through the southern towns of the district (Harvard, Bolton, Lancaster, Shirley, Groton) show many Golnik signs………not a single Tsongas or any Democrat…..I know it is early. BTW: I cannot believe the number of houses for sale in the wealthier towns around here…..These are traditional Democratic strongholds.”

In a post-Scott Brown world, anything is possible in Massachusetts; Jon Golnik has shown a bit of fundraising ability.This is one of those races that would look different if the top-of-the-ticket race, in this case, the governor’s race, were a GOP rout. Maybe something might happen here; it would be nice to see a poll.

Ohio: “I think Rich Iott is a guy that deserves a bit of a bump as you list off those with a chance to take out an incumbent Dem.The guy has been spending quite a bit of his own money already. And I hear the internal poll numbers are looking pretty good. They are still down by a few points, but there are definite indications that Iott has a shot at this thing.”

Self-financing candidates obviously have the advantage of knowing that if nothing else, they’ll have the resources to compete. If, in late October, they think another $100,000 in television ads mean the difference between victory and defeat, they just break out the checkbook. Iott’s an intriguing candidate, and it’s possible he’ll be buoyed by strong GOP campaigns at the top of the ticket in the governor’s and Senate races. The problem is the incumbent Democrat, Marcy Kaptur, is pretty well entrenched. She’s had the seat since 1982 and usually wins 70 percent of the vote or more. The Toledo-based district scores D+10. I suppose he should be on the list of potentially competitive, particularly with unemployment in Toledo at 11.6 percent.