the only reason they are looking in the Yellow Pages anyway. If you speak Spanish and that is important, make sure you tell your reader, "Si, se habla español."   Insist on Seeing a Proof   Even the best phone directories arent always accurate. But there are so many things you can get wrong on a Yellow Pages ad that it would be suicide not to get a proof before it gets printed. Barry Maher, a Yellow Pages expert, shares several stories where a mistake in just a letter or two in an ad has meant disaster.   One plumbing company had their non-local address printed in their ad three years running, which dropped calls from 40 per day to only four. A dental ad went south when his slogan ran, "Where Caring Treatment Costs More" when it should have been "Where Caring Treatment Costs No More." He had people calling in asking how much more. Another ad for a therapist read, "Dan Hadley, the rapist" but was supposed to read, "Dan Hadley, therapist."   Are Bigger Ads Better?   Yes, ad size definitely matters, but you can waste a small fortune buying more than you should. All other things being equal, bigger ads do get a greater response. They also get the best placement, which is at the front of your category. Sometimes placement can be even more important than size. The good news is that all things are seldom equal. Your ad, which may not be the biggest, or sitting right up front, can be just as effective, or even more effective, than a gigantic ad at the front of the heading.   The first thing to do is have your rep show you where you would be placed, based on the size of the ad youre considering. This should give you a good idea about your relative position. Determine if you can move up a little by making your ad the next size bigger without a big jump in cost, or move back a little by reducing your ad size without a significant shift in placement but a reduction in cost.   Determining the Optimum Size of Your Ad   Remember, all things being equal, a larger ad will increase its pulling power by a larger percentage than the difference in cost. Suppose you currently run a simple listing and get X responses. If you went to the smallest available "display" ad (usually a 1/16thpage), you should get 13X responses for only a few times the cost.   If you further increase its size to a 1/8thof a page, your cost will less than double (because of volume discounts), but youll pull another 5X the response. If you go from a 1/8thpage to a 1/4thpage, your cost less than doubles again, and your response should jump by another 3X. Increasing a 1/4 page ad to a 1/2 page ad brings in another 3X response, again for less than twice the cost.