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BOSTON ( TheStreet) -- If we're at the outset of a September correction, it's time to play defense. Here are three stocks that would grow even in a tepid economy.

These companies offer products that would gain appeal in a prolonged recession, or stand to benefit from economic stimulus funding. If the S&P 500 Index reverses its 14% climb this year, they might be good stocks to own.

Ralcorp ( RAH) is a solid bet if you expect consumer spending to remain weak. The St. Louis-based company sells generic food products in the U.S., but it also owns Post cereals, which it bought from Kraft Foods ( KFT) in late 2007.

Fiscal third-quarter net income rose 63% to $75 million, but earnings per share fell 32% to $1.31, hurt by a higher share count. Revenue surged 51% to $994 million. Its gross margin jumped from 21% to 31% and its operating margin rose from 7% to 13% on higher prices and cost containment.

A fourth-quarter net margin of 6.4% compares favorably to those of competitors Conagra ( CAG), Dean Foods ( DF) and Tyson Foods ( TSN). Although large caps Coca-Cola ( KO), PepsiCo ( PEP) and Kellogg ( K - Get Report) enjoy wider spreads and brand power, they become vulnerable as consumers shift to cheaper food, a trend that benefits Ralcorp.

With a forward price-to-earnings ratio of 13, the stock is about 20% cheaper than food products peers. Shares trade at just 1.4 times book value, less than the Russell Midcap Index average of 1.9.

Ralcorp has a beta, a measure of market correlation, of 0.2. Our model gives the stock a volatility score of 6.8 out of 10, higher than the "buy"-list average of 4.6. Ralcorp is poised for stable growth in any economic scenario. The downside is that the company doesn't pay dividends.

Its shares have advanced 9.8% this year, trailing the 14% rise of the S&P 500. However, the stock has gained 2.1% in the past year, while the benchmark dropped 18%.

Another stock that's likely to grow is ManTech International ( MANT - Get Report). This firm has carved a niche in "cyber warfare," the use of computers and the Internet to intercept sensitive information. Technology is playing an increasingly important role in intelligence gathering and defense, helping ManTech attract more business from customers such as the State Department, NATO and NASA.

ManTech is a model of recessionary expansion. It achieved a 12-month growth rate of 15% for revenue and 26% for net income. Second-quarter profit advanced 30% to $29 million, or 80 cents a share, as revenue grew 11% to $514 million.

The company purchased DDK Technology in March and EWA Services in December. By acquiring smaller firms, ManTech minimizes damage to its balance sheet, suffers fewer integration problems and maintains flexibility for future purchases.

The company's ties to government agencies and niche focus add safety to its stock. A beta of 0.3 indicates low volatility. By comparison, defense contractors Boeing ( BA - Get Report), Lockheed Martin ( LMT - Get Report) and Northrop Grumman ( NOC) have betas higher than 1.

ManTech has fallen 3% this year, lagging behind major U.S. indices. The stock trades at a forward price-to-earnings ratio of 16, a discount to tech consulting peers, but a premium to defense contractors.

The company's balance sheet is its strongest selling point. ManTech paid off $100 million of debt in the second quarter, leaving it with $33 million of cash and $20 million of debt.

ManTech's hefty backlog, tech expertise and financial strength make it a viable target for a larger defense contractor; another reason to buy its shares. Like Ralcorp, the company doesn't pay dividends.

Computer Programs & Systems ( CPSI - Get Report) installs and supports computer systems in hospitals and clinics. Hospitals, traditionally unprofitable businesses, have been slow to upgrade record-keeping systems. Assistance from Uncle Sam is releasing pent-up demand.

A three-year growth rate of 2.7% for revenue and 1% for net income are disappointing. But during the past year, revenue has jumped 9% and net income climbed 22%.

Computer Programs' second-quarter earnings rose 18% to $3.5 million, or 32 cents. Its gross margin fell from 45% to 42%, but its operating margin remained steady at 17%. The company has an ideal financial position, with no debt and ample liquidity, evident in a quick ratio of 3.8.

The stock has ascended 47% this year, outpacing major U.S. indices. At a forward price-to-earnings ratio of 22, the stock is 43% cheaper than health care technology peers, but more expensive than the market average.

Shares offer a 3.7% dividend yield, higher than the average of S&P 500 companies. However, the company's quarterly payout ratio, a measure of dividend safety, is excessive at 112%. That means the dividend isn't being funded by earnings alone and is vulnerable to a cut.

Then again, as stimulus funds are distributed, business will increase, making a payout decrease unlikely in the near-term. Computer Programs has a beta of 0.5, indicating below-average volatility. It is a play on public sector spending and health care growth.

-- Reported by Jake Lynch in Boston.