Investors often turn to recommendations made by Wall Street analysts before making a Buy, Sell, or Hold decision about a stock. While media reports about rating changes by these brokerage-firm employed (or sell-side) analysts often affect a stock's price, do they really matter?

Before we discuss the reliability of brokerage recommendations and how to use them to your advantage, let's see what these Wall Street heavyweights think about Intuitive Surgical, Inc. (ISRG).

Intuitive Surgical currently has an average brokerage recommendation (ABR) of 1.70, on a scale of 1 to 5 (Strong Buy to Strong Sell), calculated based on the actual recommendations (Buy, Hold, Sell, etc.) made by 23 brokerage firms. An ABR of 1.70 approximates between Strong Buy and Buy.

Of the 23 recommendations that derive the current ABR, 14 are Strong Buy and two are Buy. Strong Buy and Buy respectively account for 60.9% and 8.7% of all recommendations.

Check price target & stock forecast for Intuitive Surgical here>>>

The ABR suggests buying Intuitive Surgical, but making an investment decision solely on the basis of this information might not be a good idea. According to several studies, brokerage recommendations have little to no success guiding investors to choose stocks with the most potential for price appreciation.

Are you wondering why? The vested interest of brokerage firms in a stock they cover often results in a strong positive bias of their analysts in rating it. Our research shows that for every "Strong Sell" recommendation, brokerage firms assign five "Strong Buy" recommendations.

This means that the interests of these institutions are not always aligned with those of retail investors, giving little insight into the direction of a stock's future price movement. It would therefore be best to use this information to validate your own analysis or a tool that has proven to be highly effective at predicting stock price movements.

With an impressive externally audited track record, our proprietary stock rating tool, the Zacks Rank, which classifies stocks into five groups, ranging from Zacks Rank #1 (Strong Buy) to Zacks Rank #5 (Strong Sell), is a reliable indicator of a stock's near -term price performance. So, validating the Zacks Rank with ABR could go a long way in making a profitable investment decision.

Zacks Rank Should Not Be Confused With ABR

In spite of the fact that Zacks Rank and ABR both appear on a scale from 1 to 5, they are two completely different measures.

Broker recommendations are the sole basis for calculating the ABR, which is typically displayed in decimals (such as 1.28). The Zacks Rank, on the other hand, is a quantitative model designed to harness the power of earnings estimate revisions. It is displayed in whole numbers -- 1 to 5.

It has been and continues to be the case that analysts employed by brokerage firms are overly optimistic with their recommendations. Because of their employers' vested interests, these analysts issue more favorable ratings than their research would support, misguiding investors far more often than helping them.

On the other hand, earnings estimate revisions are at the core of the Zacks Rank. And empirical research shows a strong correlation between trends in earnings estimate revisions and near-term stock price movements.

Furthermore, the different grades of the Zacks Rank are applied proportionately across all stocks for which brokerage analysts provide earnings estimates for the current year. In other words, at all times, this tool maintains a balance among the five ranks it assigns.

Another key difference between the ABR and Zacks Rank is freshness. The ABR is not necessarily up-to-date when you look at it. But, since brokerage analysts keep revising their earnings estimates to account for a company's changing business trends, and their actions get reflected in the Zacks Rank quickly enough, it is always timely in indicating future price movements.

Is ISRG a Good Investment?

Looking at the earnings estimate revisions for Intuitive Surgical, the Zacks Consensus Estimate for the current year has remained unchanged over the past month at $6.18.

Analysts' steady views regarding the company's earnings prospects, as indicated by an unchanged consensus estimate, could be a legitimate reason for the stock to perform in line with the broader market in the near term.

The size of the recent change in the consensus estimate, along with three other factors related to earnings estimates, has resulted in a Zacks Rank #3 (Hold) for Intuitive Surgical. You can see the complete list of today's Zacks Rank #1 (Strong Buy) stocks here >>>>

It may therefore be prudent to be a little cautious with the Buy-equivalent ABR for Intuitive Surgical.

Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report

Intuitive Surgical, Inc. (ISRG) : Free Stock Analysis Report

To read this article on Zacks.com click here.

Zacks Investment Research