One of the questions I get asked most frequently, having been a New Jersey restaurant critic for almost 20 years now, is what I think of Yelp, the crowd-sourced review site. Almost everyone expresses surprise when I reply that I find it useful, even though its reviews are penned by the public (or as we critics call them, amateurs).

Of course, my endorsement comes with a slew of caveats — and these go well beyond the flaws allegedly built into the Yelp business model. Yelp has been accused by restaurant owners of directly pressuring them to advertise and, failing that, resorting to manipulating which positive and negative reviews get posted and taken down, and even constructing spam reviews to further turn the screw. (To date, neither FTC investigations nor lawsuits have resulted in any action against Yelp.) My personal caveats focus instead on how to reliably assess a restaurant by parsing those reviews that manage to get and stay posted.

The first thing I ask people is how much time they’re willing to invest, because briefly skimming the first five or even ten reviews isn’t enough to elicit a reliable picture. And while the total raves (i.e. 5 stars) and vicious pans (1 star?) often make for hilarious reading, they’re almost always hyperbole.

Plus, how annoying is it that Yelp reviews don’t always appear in chronological order? I mean, restaurants change for better or worse all the time: they lose and gain chefs, managers, and particularly service staff. So do I really care what someone did or didn’t like in 2013?

People are startled when I say I think a restaurant’s overall star rating does have validity, but only for restaurants that have corralled a good number of reviews — by which I mean 150 or more. If a restaurant has been open three months and has accumulated 17 reviews, that tells me zilch. And if it has managed to score a unanimous 5-star rating over that time, I know that those reviews have likely been posted by the restaurant’s staff, friends, and family.

After writing that last sentence, I googled “restaurants Princeton NJ Yelp,” and was startled to come upon pretty much that exact situation for a new Princeton restaurant: Aurelio’s Cocina Latina, which I featured in my “Food for Thought” column in the July Echo. Those 17 stellar ratings earned it the number three spot on Yelp’s “10 Best Restaurants in Princeton” list.

It’s a fine restaurant, but really? Restaurants that did not break that particular top ten include the Peacock Inn and Agricola, and perennial local favorite Teresa Caffe came in at number 10. Do these rankings represent reality?

Even worse, when I returned to the Google list for “restaurants Princeton NJ Yelp,” and chose the next hit in the sequence, photos of five eateries popped up under Yelp’s heading of “Best Restaurants in Princeton.” The list: Hoagie Haven, Blue Point Grill, Teresa Caffe (!), Cross Culture, and the Peacock Inn (in no particular order). What the heck? No Aurelio’s? And a list of five “Best” doesn’t mimic half of the “10 Best?”

So I go back out to the list of Google results and this time choose the one for “Best of Yelp/Princeton Restaurants” and still a different set pops up. Mind you, all of these lists are at yelp.com. The five therein are Blue Point Grill, Hoagie Haven, Cross Culture, the Peacock Inn, and Infini-T Café. So how does Infini-T finish here but not on the preceding Yelp lists? All I came away with from this confusing escapade is that, in fact, Blue Point Grill and Hoagie Haven are best bets. No argument there.

To test out my strategy for how to get a credible line on a restaurant, I then read the latest 25-plus entries for Blue Point Grill, which as of that moment had 365 reviews and a 4-star rating. These same comments showed up time and again:

–Simple but impeccably fresh seafood

–Pleasant outdoor seating

–BYOB a plus

–Pricey but worth it

–Knowledgeable, helpful staff

I think that’s a pretty accurate assessment of that restaurant’s strengths. Someone deciding to dine there for the first time because of the Yelp comments would likely not feel misled. I noted that although certain specific dishes were praised several times, in general these likes (and also dislikes) were highly personal, so I would use them more as a guide to what the menu has to offer, but not what I might actually order.

As to which particular reviews I heed: once a restaurant’s listing meets the above requirements of having been around a while and having accumulated an adequate number of reviews, here I must confess to terrible snobbery. When users tag a dish “tasty,” “yummy,” “amazing,” or “awesome,” and I’m onto the next entry. Ditto for equally unhelpful negative terms, like “yucky.”

And the frequency and number of exclamation points in a review determine exactly how quickly I scroll past it. Or be too effusive in your judgments — “Sushi better than Nobu,” “Better than fantastic!” — and you are dismissed.

I am embarrassed to own up to this next weeding-out strategy. If your words indicate that you are very young or very old, that will color my reading. I won’t outright dismiss your comments, but I will allow age to influence how much weight I give them. What’s an example of an old-timer’s comment? One that starts with “The food was served hot…” See “yucky” and “yummy,” above.

Even if you fall within my approved age range, I will cast a gimlet eye on your critical abilities if you inadvertently reveal that you’re an inexperienced diner. One contributor watched the Blue Point Grill staff open oysters to order, but seemed unsure if he should refer to this act as “shucking.” How much could he really know about enjoying tasting?

Here’s another: “If you enjoy weird food, you’ll like this spot. I, however, just want chicken nuggets, Cheerios or a cheeseburger. None of which were on this menu.” A grown woman wrote that about Mistral. I’m not proud of my snobbery, but on the other hand I suspect you have prejudices of your own.

One area of critique that I almost never pay attention to is service. Opinions on what constitutes good or deficient service vary as much as what constitutes good pizza. And over the last two decades I’ve often found that many a customer’s behavior at restaurants can be downright appalling. You show up without a reservation and have to wait 45 minutes, so the restaurant gets 2 stars on Yelp? Really? One Yelper allots a restaurant 2 stars because the food was “great but not fabulous.” I am not making this up.

Here are examples of comments and reviews about Princeton restaurants that I find germane, insightful, and helpful:

“[I give it] 4 stars for my Princeton standard, but 3 stars compared to my LA/NY standard.” Don’t you know exactly what she means?

“During our meal people who passed behind my husband would occasionally kick his chair, which annoyed him a bit, even after we moved the table a bit towards me, but oh well.” This is a valid criticism – and one I would be less gracious about than her husband.

“Nitpicks: Runners had no clue which dish was for who; no silverware change between courses; disposable napkins; unisex bathrooms. For this kind of money I don’t want the last course’s sauce still on my knife, I don’t want to ask for more napkins, and I sure don’t want to stick my finger up like I’m hailing a cab to declare which dish is mine when the runner arrives.” Totally on point.

“A diverse but simple and fresh menu. They feature farm-to-table and emphasize sustainability. The salads are always fresh. The cheese board with honeycomb is a favorite.” The reviewer points out specific strengths that would be extremely helpful if this were the kind of dining experience I was looking for.

“My friend and I ordered the petit ribeye special. I expected a small but thick ribeye. What came out was a super thin ‘Ponderosa/Outback/Bonanza’ steak. I almost sent it back without tasting it. Fortunately it was tender and flavorful but still super thin and the appearance was not appetizing. My buddy ordered rare and not sure how that was possible with a steak this thin. THEY REALLY SHOULD WARN THE CUSTOMER ABOUT THIS STEAK AND HOW THIN IT IS.” I could do without the angry caps, but I agree with the sentiment.

“All of the vegetables are fresh and cooked well (mushrooms retain good texture, never get slimy) and they serve Americanos and other espresso drinks using local Small World coffee.” I’m sold.

In summary, for Yelp to be effective, you must: devote enough time to read a sufficient number of recently posted reviews, being sure to check the date since they are not always in chronological order; note that the larger the number of reviews, the higher the likelihood that the star rating will reflect or at least approximate reality; make allowances for demographics, i.e. the age and sophistication of the reviewer; and give credence to the most specific and articulate of postings, since very few restaurants are either flawless or totally reprehensible.

My last crumb of advice: unless you’re traveling to uncharted territory, rely on your personal cohort for restaurant recommendations. You’re familiar with the culinary peccadilloes of your family, friends, acquaintances, and coworkers, as they are of yours. You can’t say the same about any Yelper. And if Yelp fails you, you can always take your chances with us professional restaurant critics.

Pat Tanner blogs at dinewithpat.com.