The main cause seems to be their Expanded Broad Match system. Given any phrase describing a product in multiple words, a computer will not necessarily know the importance of the brand and/or model name or number.
Google relies on click-throughs to determine relevance. A searcher who sees an ad for one model of a product may click it hoping you'll have the model they want to buy. That makes the phrase for one model seem relevant to a search for another model so Google thinks that is great.
If the advertiser only handles specific models (which is very common) their advertising costs escalate while their conversions drop.
Advertisers who use broad match and sell specific model names and numbers can do damage control by putting all of the model names and numbers they do not handle in as negative keywords.
It would also be a good idea to put all of the other products you do carry in as negative keywords in all the other ad groups for every other product. Even if you're not seeing this issue today it can suddenly appear at any time because their system is constantly equating phrases to each other. That can cause a huge and sudden increase in advertising costs.
Doing that in a large account with ads for many specific brands, makes, and models is an enormously time-consuming task. If you want the traffic that broad match can drive (often half of all traffic and sales) it is an investment worth making.
The alternative is to only run exact match and only those phrase matched phrases that won't trigger on other searches. If you're running less specific phrase matches you'll still need to add the negatives.
You can use negative embedded keywords to control this behavior and get Google to show the ads you want shown. For example, you can add the brand name and/or generic phrases as a negative embedded keywords at the campaign or ad group level like this:
-[brand name]
-[brand generic product description]
This won't block a search for [brand name model number xxxx] so your very targeted ads will still trigger. The catch is it also won't block any general phrases with other keywords in them. So use regular negative keywords wherever possible and negative embedded keywords only when they would block your positive phrases.
Even if you do sell all the models, landing searchers on the correct product page has a huge impact on conversion rates. You do want your paid traffic to end up at the right place.
|