I often hear that you should not have more than 5-10 keywords in an ad group; then I’ll hear you should only have 1 keyword in an ad group; and Microsoft just said 20 max keywords in an ad group to keep the ad relevant.
Please note: this only goes for search campaigns. For content campaigns, Google only looks at a maximum of 50 keywords in an ad group. The info in this post only concerns ad group organization for adCenter, AdWords, or YSM as it relates to search.
The number of keywords that belong in an ad group is based upon how many keywords your ad copy describes. It is better to have more specific ad copy than more general ad copy. There is no magic number.
A great exercise is to write a very specific ad; one that is so specific that if someone reads your ad they can only assume you do this one service (or sell this one product). Then look at the keywords in the ad group. Does the ad copy accurately describe the keywords? If yes, the keyword is in the correct place. If no, then put the keyword in another ad group.
What I often see is someone writing an ad like such as:
John’s Plumbing Service
Servicing the Chicago area
Call for an appointment today!
And then a list of these keywords in the ad group (and someone claiming that the ad does describe all of these keywords):
- Chicago plumbing
- plumbing services
- broken pipes
- emergency plumbing
- 24 hour plumbing service
- fix shower
- overflowing toilet
- Saturday plumbing
- weekend plumbing
- flooded basement
- kitchen remodeling
Technically, the above should be several different ad groups. Emergency plumbing means you have a problem right now and you need someone at your house ASAP. Kitchen remodeling is a longer buying cycle, someone will want to get a quote, pick out counters, cabinets, etc – there is time before the final conversion. These two items are very different user intents.
Now consider the below list. Each highlighted color represents an ad group (ignoring how good/bad the ad copy is – it’s specific):
In this organization, the ad copy is more specific to the user’s search intent. Therefore, the ad copy is much more likely to receive a click.
If you consider the consumer, weekend plumbers is someone who doesn’t chart $500 an hour to come to your house on a Saturday. Emergency plumbing is someone who needs something done right now regardless of day or time. Fixing a shower can usually be done by appointment by most plumbers.
Consider your audience and what scenario is happening in their life that would cause them to do that particular keyword search.
You may have a few general ad copies at the end of your organization. However, you should end with these ad groups (sort of your left over keywords) and not start there.
Start with the most specific keywords, write targeted ads for them, and then go more general with words that do not fit into the most specific ad groups.
If you write a very specific ad and it does describe a thousand keywords; then that’s OK. It’s not that uncommon to see well organized ad groups with a thousand keywords. It’s much more common to see an ad group with a thousand keywords be disorganized; hence where some of the max keywords per ad group advice comes into play.
If you do the hard part of organizing your ad groups correctly, then there is no magic rule of thumb for how many keywords should be in an ad group. The number is what makes logical sense. You may have ad groups with only one keyword. You may have some with two thousand keywords. Don’t worry about the number if the account if organized correctly.
This is the most time consuming part of PPC; however, it will give you the best chance of long term success.