If you’re in the retail business, you know it’s one matter to prevent theft after hours, when buildings are empty, lights are off, alarm is on, and the doors are locked. Keeping out shoplifters is a whole other story. An annual survey reported that, last year, more than a fourth of the $35 billion in lost sales was caused by shoplifting.

No one wants to alienate customers with undue suspicions and inconvenient security measures. Prevent shoplifting losses the discreet, friendly way, by training your employees to do the following:

• Greet everyone. This is good business in and of itself, because it presents your store as a welcoming, safe environment. It also sends a message to potential shoplifters that they are not anonymous, unnoticed browsers, who can do as they like.

• Offer help, especially if you notice a customer who seems to linger in one area without touching or browsing. He/she may simply be a confused buyer who needs help understanding the product line. But if he/she is a shoplifter waiting for an opportune moment, he/she now knows it’s too late.

• Keep a shoplifting log, privately. This can be a white board or a notebook in the back room, someplace customers will never see. It’s a community diary in which your employees can write down suspicious incidents, such as customers who enter and leave repeatedly, or who linger in spots that are hard to monitor. They can give descriptions of the person in question and log losses that may have occurred that day. That way everyone can be on the same page, and know what to watch for in the future.