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Beware the “N = 1”

Business solutions that worked for one practice may not work for all.

Gary Gerber, O.D.

When you prescribe a glaucoma drop, you expect it to work. You understand the drug has been put through the rigors of the FDA approval process, so it has been used on many patients and a majority of them have experienced the desired effect.

You also understand that even though a drop might have lowered IOP by an average of 10mmHg in 90% of patients, there are no guarantees it will work for your patient. That’s why when you prescribe it, you require a follow-up visit.

On to business advice

But what do we know about the practice management advice we hear regularly, such as, “join vision care plan A,” or “you should carry 946 frames in your optical, and mark them up 2.6 times”? In response, astute practitioners should ask: “Where does the advice come from? Has it been put through the rigors of testing and if not, should I blindly follow the advice and hope it works for my practice?”

In reality, such information is rarely (if ever) tested. The purveyor might have had great success with a technique. But, just like idiosyncratic medicine reactions, this doesn’t mean the exact same technique will work for your practice.

Here’s an example: Let’s say a lecturer recommends discounting second pairs of glasses by 30% as a means to stimulate sales. The speaker argues “in this economy, patients won’t buy the second pair of glasses without a discount.”

Taking this advice, you institute the discount, and more patients do indeed buy second pairs. But, after a week or so, sales slip back to previous levels.

What happened?

In this case, it wasn’t a lower price that caused the brief increase in sales. Rather, the doctor felt empowered to talk about the second pair and used the discount as a verbal crutch. After a few days, this became the new norm, and the doctor once again feared that patients would perceive him as a “heartless eyeglass hawker” who wasn’t really concerned with patients as much as his bottom line. So, the doctor stopped talking about second pairs, and sales stopped.

In this example, the reason for the doctor’s failure to sustain second pair sales had nothing to do with their price and everything to do with his resistance to discuss them. The expert should have recommended communication skill training for the doctor and not a discount. How did he get it wrong?

Simple: The “expert” based his 30% discount findings on a sample size of one, or “N = 1.” He is in effect saying, “I did this in my practice and it worked, so you should do the same in your practice.”

An analytical approach

A better approach would have been for the doctor to first ask himself, “Why don’t I sell more second pairs? Is it price? Selection? Lack of awareness and discussion with patients? All these?” From there, the proper solution could have been put into place. In this case, the doctor would have kept his margins much higher and ultimately done much better by simply believing his patients needed second pairs and discussing them. No discount needed.

Advice from experts is fine when it’s really expert advice that is based on sound business principles and not solely the experience of one person or practice. Just like you wouldn’t treat a patient based on an “N = 1,” don’t “treat” your practice that way either. OM