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

What: Shares of PAREXEL International (NASDAQ:PRXL) climbed 3% today after ISI Group upgraded the clinical research organization from "neutral" to "buy."

So what: Along with the upgrade, analyst Ross Muken boosted his price target on the stock to $57 (from $52.50), representing about 15% worth of upside to yesterday's close. While value investors might be turned off by PAREXEL's hot streak in 2013, Muken thinks strong trends in favor of CROs should provide plenty of fuel for even further price appreciation.

Now what: ISI thinks PAREXEL is in a particularly good spot to capitalize from sector tailwinds.

"Our view of the CROs is positively biased by (1) improved pipeline success rates at biopharma (after several years of contraction, NME approvals were up from 21 to 30 to 39 in 2010-2012, with 16 NMEs thus far in 2013); (2) a rebound in biotech funding (2Q'13 biotech funding up ~40% sequentially and ~70% y-o-y); and (3) continued vendor consolidation among sponsors (the 7 largest CROs have grown from ~35% of the market in 2004 to nearly 60% today)," noted ISI. "We believe these trends should benefit the large diversified late phase CROs with global presence and full-service offerings (far better suited for integrated strategic partnerships)."

Of course, with the stock now up about 80% from its 52-week lows and trading at a 30-plus P/E, I'd wait for the excitement around those trends to fade a bit before jumping in. 

Fool contributor Brian Pacampara has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.