Methodology is destiny when conducting a study.

A study conducted by San Diego’s Utility Consumers’ Action Network, which purports to show cell-phone users pay an average of $3.02 a minute, falls somewhere between skewed and laughable.

The consumer group’s conclusions: Deregulation has increased costs for some local services as much as 346% and -- get this -- “There is no meaningful phone competition for San Diego households.”

Whew! That’s a lot to swallow. Let’s hope it’s satire.

Apparently, Verizon (VZ), AT&T (T), and Sprint Nextel (S) are neither phone companies or competitors for purposes of this study.

First, the sample size of “over 700” raises the basic question of validity. The latest estimate by the California Department of Finance pegs San Diego’s population at about 1.3 million. That means the survey sampled about 0.0538461% of the population. Even someone high on life wouldn’t call that a representative sample.

The study assumes that most customers use only a small percentage of the airtime they buy each month. If so, this drives up the cost per minute. Well, duh. Don’t buy more time than you’ll use - unless you feel compelled to make monthly contributions to your good pals at the phone company.

It’s hard to tell from the group’s summary of the study, but it appears a good chunk of the survey population spent about 10 to 15 minutes -- or less -- on the phone each month. Is that you or anyone you know?

Once again, dear consumer group: Don’t buy more time than you need.

The study also ignores text messages - an increasingly popular form of communication, especially among kids. Failure to include time used sending text messages artificially inflates the cost per minute.

The consumer group warns darkly that fees and taxes are added on to the basic monthly fee, further driving up the cost of each call. Zowie - someone went to the mountaintop to come back with that vital insight. There's no cure for fees and taxes, but the smart customer reads the contract before signing on the dotted line.

San Diego Utility Consumers’ Action Network says that unlimited land-line packages are also a bad deal, costing users an average of $0.55 a minute. This is getting tedious: If you don’t yap a lot on the phone, don’t buy service that you won’t use!

You can bet the usual suspects will quote the study as gospel, and jaws will drop as some nattering ninny proclaims, “The average cost of a cellular phone is $3.02 per minute."

Yeah, sure. But take a look at the study’s purported methodology before accepting this tripe as gospel.