This post by Dan Tolensky on the Leafs' recent signing of Jeff Finger was an interesting read. Tolensky shows how Leafs GM Cliff Fletcher and coach Ron Wilson were completely wrong in their descriptions of Finger's role on his team. Wilson and Fletcher claimed that the defenceman was matched up against the Western Conference elite, even though Finger actually played the opposition of a bottom-pairing defenceman. And of course, even though the Leaf management was demonstrably wrong in their assessment there were many Leaf fans defending their coach and GM in the comments because they were "experienced" hockey "insiders".
So what went wrong, are Fletcher and Wilson lying about Finger? Trying to cover up for their mistake? I don't think so - I think they genuinely believe what they are saying. They merely, to borrow a term from Lowetide, "saw him good", i.e. saw Finger play a few times when he was doing exceptionally well and assumed that to be his usual standard of play. In the case of Wilson, maybe he remembers Finger rubbing out Thornton once or twice and figures that they must have played against each other the whole game. Worst of all, the Leafs never took the time to look up the numbers and check whether their perception matched the reality.
This isn't just limited to hockey, of course, you can find these types of mistakenly false statements in all professional team sports. Fire Joe Morgan is one of the best at repeatedly catching and pointing them out (such as, for example, this one by Dusty Baker).
Professional GMs, coaches, and scouts see hockey players (and goalies) in small sample sizes, and make conclusions about them. Sometimes they glean valuable insight by watching a player, and sometimes they get it completely wrong. In an example of the latter case, you have a 28-year old forward who scored a career-high of 51 points while playing on the wing of an MVP candidate signing for $31.5 million over 7 years because of a few big goals and some gritty play (read: broken noses) during the past playoff season. Or, to use a goalie example, the spread of the perception that Manny Legace is a backup goalie and not a #1 because of his career record in 11 playoff games.
That is why I do not place a great deal of emphasis on what one individual hockey insider says about a player. For almost any player in the league you can probably find someone who will describe them in glowing terms, just because they saw them play well, or because they have ties to that player as a former teammate or coach. There is a lot more value in the league consensus on a particular player, but even that opinion is also greatly influenced by groupthink and the prevailing popular opinion - e.g. a lot of people haven't seen Brodeur play much over the last couple of seasons, but figure that he must be the best goalie in the league because everyone else says so. I'm not saying professional scouting or expert opinion has no value but merely that it is subject to biases and should be combined with a thorough statistical analysis to make sure that the sample viewed didn't include only the best or the worst of a specific player or goalie.
This also reinforces how unreliable our memories are - if Ron Wilson can misremember who Jeff Finger played against while he was coaching against him just a few months ago, then how can any fan accurately remember how, say, Grant Fuhr performed late in the third period of close games in the playoffs two decades ago? What often happens (as I speculated about Wilson) is that single plays take on disproportionate impact in shaping a player evaluation. So in the case of Fuhr, people remember a few big overtime saves from the 1987 Canada Cup or the 1988 Stanley Cup Finals and as a result always think of Fuhr as a clutch goalie. I have blogged before about how one long shot goal sunk Tony Esposito's reputation as a big-game goalie. Chris Osgood is another goalie who was stigmatized by a few weak goals against in the playoffs, and it is impossible to have an argument with a Patrick Roy hater without them repeatedly bringing up Roy accidentally dropping the puck and giving up a goal against Detroit in the 2002 playoffs.
There are biases in scouting that can lead to big mistakes, even evaluations of relatively recent performances by experienced individuals in charge of running NHL teams. As a result, in the vast majority of cases I prefer to put my trust in the numbers to find out if someone is good or if I've just seen them play well.