If you want to move up, don't dress down.

Ten years ago, if you looked out your window in the morning and saw your neighbor dressed as if he's going camping, you'd assume he's on vacation or perhaps taking one of those "mental health" days. No more. Today, he could be heading to work - and not to a construction site but to an office.

More and more firms are allowing some form of casual dress at work at least part of the time. Some firms call them "Casual Fridays," limiting the slovenly dress to one day a week; others call them dress-down days and may spread them freely throughout the year.

Workplace Vitality magazine recently reported that 67 percent of the hundreds of firms contacted in a 1995 employment survey now permit casual dress. But my informal survey of friends and family says the number is closer to 99 percent. And that scares me.

For starters, why should Friday be a day when employees dress down? It's not a day off, and I assume most executives expect the same amount of work from their employees on Friday as on every other day of the week. I know I do. I've never heard of a company that pays employees at a lower rate for Friday work. A quick calculation tells me that Friday represents 20 percent of the work week!

I admit that measuring productivity in an office by comparing one day to another is difficult, but I believe if dressing down has an effect on productivity, it's only negative. If you look sharp, you're more likely to act sharp. I suspect that's one reason our military requires a certain standard of dress. In New Dress for Success, author John Molloy supports that theory when he writes, "Research conducted by two companies independent of each other (one with blue-collar workers and the other with office workers) found that employees who were neat and well put together performed better than employees who were not. It may be due to the fact that [the neater] employees have a better self-image, and therefore perform at a higher level ... ."

I expect a host of people will come forward and say that dressing down actually improves productivity because employees are happier when they're dressed that way. After all, they're more relaxed. But I don't want my employees to relax. I want them to work. If wearing regular business attire makes them even a little bit more inclined to work, then I don't want them in dungarees.

Sure, some people will work at the same productivity level even if they're butt naked, much the way some people will work at the same intensity level whether or not the boss is around. I just don't think this rule applies to the majority of people. And, no, dressing down doesn't necessarily mean your employees will look like slobs, but what organization hasn't had someone push the definition of casual? It's like moving the speed limit on interstates to 65 - now everyone drives 75.

ALONE IN A SEA OF SWEATSUITS

I should admit that my observations about how casual dress affects productivity are limited to watching employees in other groups. While my company observes Casual Fridays, I strongly encourage the employees in my group to dress professionally. And virtually everyone accepts the encouragement.

I do this for a couple of reasons. First, as I said, I think dressing down adversely affects productivity. Second, I think most people will agree that we're influenced by how others dress. If not, why do all those how-to-interview books tell you to always look your best? Even if I were fortunate enough to have hired staff members who are completely unaffected by how they dress, I'd still encourage them to always dress professionally because it influences the perception other employees have of our department.

My staff, like most finance and administrative staffs, doesn't generate revenue for the company. We're "overhead," a reviled term in our business. (A quick turn to the glossary: Overhead is what employers spend money on instead of maintaining or improving benefits. High overhead is what keeps companies from being more competitive and winning more work to make jobs more secure.) I don't want other employees in the company to think our group is anything less than 100-percent professional and dedicated to the job. I don't want someone to say, "Why don't they cut one of those accounting positions instead of raising my insurance deductible?" Our coworkers are less likely to resort to those kinds of opinions when we look like we're working, not going to a picnic.

What's more, the people in other departments are our department's customers. They wouldn't dress down in front of their customers, so what gives us the right to dress down in front of them? Remember, your senior vice president from operations may see a member of your staff only once a week, but, from that one interaction, he'll form his impression - right or wrong. Why not increase the odds the interaction leaves him with a positive feeling?

WHOSE IDEA WAS THIS, ANYWAY?

And think of your employees' development. Giving them the "opportunity" to dress in something less than normal business attire no more benefits them than rating average employees as outstanding does. Both practices may make people feel good, but that doesn't mean they're right. (I'm guessing that's what got us into trouble in the first place: Casual Fridays were probably the brainchild of some well-intentioned but misguided human resources manager who wanted to make everyone feel good. On the other hand, it could have been a marketing genius at Britches.)

Finally, I'm proud of my position in the company. I've worked very hard to get here, and I'm good at what I do. I want to look like someone who's successful. I want the people who work for me to be proud of me and proud of their positions. They happen to work for the best finance and administration department in the world. They should look the part.

Mr. Falconi, CFO of Planning Systems Inc., a high-tech scientific and engineering firm in McLean, Va., prefers gray suits and red ties. You can reach him at [phone].