While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking analyst upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Paychex (NASDAQ:PAYX) gained 1% on Tuesday after Goldman Sachs resumed coverage on the payroll processing giant with a "conviction buy" rating.

So what: Along with the bullish call, analyst James Schneider planted a price target of $49 on the stock, representing about 18% worth of upside to yesterday's close. So while momentum traders might be turned off by Paychex's year-to-date price weakness, Schneider's call could reflect a sense on Wall Street that its growth prospects are becoming too cheap to pass up.

Now what: According to Goldman, Paychex's risk/reward trade-off is rather attractive at this point. "We believe market concerns around intensifying competition from cloud vendors are overdone, and think Paychex's integrated approach to payroll and HR services supported by a broad-based services model will continue to differentiate it," said Schneider. "In our view, this is evident from continuous improvement in operating margins and growing client retention rates, in spite of the noise around cloud cannibalization." Given Goldman's solid stock-picking track record -- currently ranked in the top 15% of our CAPS community -- value-oriented Fools might want to take a closer look at Paychex.