NEW YORK (CNN/Money) - With all the earnings warnings and accounting worries, the Nasdaq has been a fairly gloomy place.

The index is down about 150 points (roughly 7 percent) from where it was in early March, and first-quarter earnings, due to start rolling in over the next couple of weeks, aren't expected to be so great. Analysts expect tech earnings to come in about 25 percent lower than the first quarter of 2001, according to First Call/Thompson Financial.

But hopes are still high for a solid recovery in the second half of the year. Consider the following analysis.

• The consensus among Wall Street's experts, an article in Fortune notes, "is that the current slowdown will be nothing but a bad memory by the second half of the year."
• And with the economy improving, tech spending is bound to pick up as well. "Right now there's a spending freeze in place [for] IT budgets," one analyst tells Reuters. "Things look like they're going to improve from here."
• And all that bodes well for stocks. "As investors get confidence that we will, in fact, see growth in the second half of the year," another analyst opines, "all the ingredients are in place for a pretty decent market."

Sounds great. There's just one catch: all these quotes are actually from early 2001, and one year later, that recovery still isn't here.

The point of this bait-and-switch is merely to remind you to take current predictions of a second-half recovery with more than a grain of salt.

Analysts are at least as optimistic about the rest of this year as they originally were about the second half of last year. Indeed, according to First Call, analysts currently expect tech earnings in the third quarter of this year to shoot up more than 130 percent year-over-year (and that's after a 37 percent increase expected in the second quarter). For the full year, analysts expect tech earnings to be up more than 40 percent from last year.

But Chuck Hill at First Call has been saying for months that he sees analyst estimates as being too optimistic, and I suspect he's probably right.

Still, no one knows for sure, which is why sharp investors demand a "margin of safety" as insurance in case anything goes wrong. Trouble is, many tech investors these days are so worried about missing the next big run up they aren't paying much attention to risks, or to valuations.

Most tech names out there, particularly the big caps, look expensive -- given not only the considerable uncertainty about tech earnings in the near term but also, and more importantly, the real possibility that the next tech boom won't be anywhere near as robust as the last one.

A couple of weeks ago, I found my e-mail inbox clogged with dozens of angry and sometimes abusive e-mails after I suggested that a return to Nasdaq 5000 could easily take a decade or more. I thought this assertion would have been relatively uncontroversial. After all, a 10-year projection assumes a not-too-shabby 10 percent annual return.

But too many tech investors aren't even willing to entertain the possibility that the next tech boom won't be, as William Shatner once said about Priceline, "big, really big." Despite the tech crash, a surprising number of investors still seem to think that 20-plus percent annual returns on tech stocks are simply their due.

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My e-mail correspondents aren't the only ones infected with excessive bullishness: the latest poll from the American Association of Individual Investors reports that some 51 percent of investors are feeling bullish these days (and only 23 percent bearish). Numbers like these indicate high levels of investor complacency; for those who see investor sentiment as a contrary indicator, that's not a good sign.

With tech investors eager to put aside bad news and embrace the good, I wouldn't be surprised to see tech stocks rally when and if some prominent tech names report better-than-expected earnings later this month. I'd be far more surprised if these rallies were to last.

These days, that's about as close to a prediction as I'm willing to get.

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