Underpromise. Overdeliver. That's the mantra that drives earnings surprises. For investors, the treat is especially sweet because it means that professional bean-counting analysts have underestimated a particular company's profit power. That often leads to more upside surprises in the future.

That said, let's take a closer look at a few of the companies that humbled the prognosticators this past week:

We'll start with Barr Pharmaceuticals (NYSE:BRL). The maker of generic drugs saw profits come in at $0.77 a share, well ahead of Wall Street's target of $0.72. The bottom line improved despite an 8% dip in revenue. While the company suffered a sales dip in a few of its low-margin pharmaceuticals, it was countered with a welcome doubling of sales in its higher-margin proprietary products. Even though it's been a rough go for many of the major drug makers with spotty pipelines and troublesome solutions already on the market, Barr and peers like Mylan (NYSE:MYL) and Ivax (AMEX:IVX) have held up relatively better by dispensing cheaper generic alternatives.

Comverse Technology (NASDAQ:CMVT) was another topper. Earnings per share more than doubled to $0.16 a share on a 23% spike in revenue. Wall Street was perched on the $0.13 per share mark, a sum narrowly bested by even Comverse's lower $0.14 per share showing in pro forma profitability. Comverse didn't beat projections by much, but it did excite the investing community with a robust backlog of orders. In other words, the next few quarters should also come along nicely. With its cash-rich balance sheet providing a fluffy cushion, it's easy to see why the market is taking a closer look at the communications technology specialist.

Jos A. Bank Clothiers (NASDAQ:JOSB) is the third company that we'll be taking a closer look at this time. This one is especially welcome given the way that retail stocks have been roughed up this summer. The upscale apparel retailer earned $0.37 a share this past quarter. That was better than the $0.33 hemline that Wall Street's tailors were expecting. Our own Nathan Parmalee took the company to task for Bank's widening cash conversion cycle, but it was a solid showing beyond that.

As far as Bank is concerned, this is the time of year when retailers report on their July quarters. There aren't too many shops trouncing the market at the moment, though Casey's General (NASDAQ:CASY) did join Bank in beating the street this past week. These companies that stand out, outperforming in an otherwise sluggish sector, may be worth looking into -- especially when the retail industry bounces back into favor.

So, keep watching the companies that lap expectations. Over time, it will be a rewarding experience for investors. That's the kind of surprise that market watchers relish in the Rule Breakers newsletter service. The strategy has paid off as the average Rule Breaker selection has more than tripled the S&P 500's market return. Want in? Check out a 30-day trial subscription.

Either way, come back next Monday to learn about more stocks that blew the market away.

Longtime Fool contributor Rick Munarriz is a fan of toppers, but he does no?t own shares in any of the companies mentioned in this story. The Fool has a disclosure policy. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.