Even the best companies make a personnel mistake once in a while. But here’s a shocker: More than two thirds of firms in a recent survey said they’d suffered through a bad hire this year.

A new CareerBuilder survey revealed that 68% of employers were affected by a bad hire in the past year — about the same  number as 2010.

The worst part: Bad hires are expensive.

Forty percent of employers reported that a new hire typically costs $1,000 or less; 34% said between $1,001 and $5,000, and 27% put that number at more than $5,000.

But the bad hires can significantly affect an organization’s bottom line. Given productivity problems and other factors, here’s what poll participants said their hiring mistake cost:

• More than $25,000 — 41%, and
• More than $50,000 — 25%.

Why do companies make bad hires? A rushed decision was the top reason companies gave for making a bad hire, but the survey found that there’s not often an easy explanation. Some alternatives:

• Needed to fill the job quickly — 38%
• Not sure; sometimes you make a mistake — 34%, and
• Didn’t check references — 11%.

And another 21% cited “insufficient talent intelligence,” whatever that might be.

What are the effects of a bad hire? Nine percent of the survey respondents  said bad hires result in legal issues and 11% said they result in fewer sales. Other ill effects:

• Lower productivity – 41%,
• Lost time to recruit and train another worker — 40%,
• Cost to recruit and train another worker — 37%,
• Employee morale negatively affected — 36%, and
• Negative impact on client solutions — 22%.

The survey was conducted among 2,696 employers between Aug. 16 and Sept. 8 of this year.

Tags: bad hires, CareerBuilder, surveys