Suggestive selling (or "on-selling" or "up-selling") is a technique employed by a sales clerk with the goal of increasing the total sale amount (basket size). The classic example is the McDonalds' cashier saying "Would you like fries with that?" Fries, being a legitimate related item, are a valid "up-sell" on a lunch order.
This Independent Retailer article makes the claim:
The lesson here is that suggestive selling not only works, but can add significant percentage to store sales volume and margin. When practiced consistently, suggestive selling not only adds additional sales and profits, but also demonstrates improved service and therefore VALUE to the customer.
It's intuitively that it could be helpful in certain establishments such as restaurants ("May I suggest a glass of our 40 year old port with that cheese platter?") or clothing stores ("This tie would go perfectly with that suit.") as the salesperson is suggesting legitimate upgrades to the purchase.
However, I've noticed that recently there is a trend in gas stations to suggestive sell unrelated items for every transaction. If I go into the gas station to buy a pack of gum, I'm persistently asked "Would you like fresh coffee or Lotto with that?"
I can't be the only person that finds it annoying. In fact, I've stopped buying my gum at the gas station. I'll actually make another stop at a variety store.
This Restaurant Doctor article, Building Sales Without Selling, seems to support my view that S.S. can be detrimental (for restaurants, at least).
Does evidence support this sales technique for retail?
I would like to see a study that examines average basket size with and without small item suggestive selling. Furthermore, we should examine total customer count with and without the up-selling technique. Does average basket size increase? Does customer count decrease? and how does this relate to total revenue?