Google released Pmax campaigns to the advertising world back in 2021. Since then it’s made quite the splash, mostly for ecommerce businesses. In my experience I constantly see the highest ROAS and Conversion Value using Pmax campaigns when advertising ecommerce websites.

First you want to be aware of the fact that by default, it will be advertising under your brand term, which will undoubtedly skew results in a positive way. Because of this, it’s better to add your branded term as a negative keyword in the Pmax campaign and just set up a separate search campaign that only targets your branded terms. This way you get more control over your campaigns and can get a more accurate picture on what’s driving conversions. 

Pmax campaigns also have asset groups instead of ad groups. They’re very similar however and you can structure your asset groups in a similar way that you’d structure ad groups. I like to create an asset group for each product category you have. This way the assets (ad copy, images, video, etc) you use can be more specific and tailored to that product category. 

You generally don’t want to have more than one asset group advertising the same products. With that said, I’ve seen some Pmax campaigns set up in a way that avoided all best practices and they still generated a high ROAS. 

Instead of targeting different product categories with each asset group you can get more granular and just target one product per asset group too. It really depends on how many products you offer and how many products you want to advertise.

When setting up an asset group you just want to make sure you’re adding as many assets as possible. This will give Google more to work with which usually generates better results over time.

Add keywords related to each asset group as the search theme for that asset group. This part is simple enough.

For audiences, in Pmax campaigns these are simply signals so your ads aren’t going to only be showing to the audiences you select, they’re just used to help guide the machine learning algorithm in the right direction. Audiences are a mix of in-market, affinity and your own data like website visits, converters, customers, etc.

I find the more data of yours you feed it the better typically. For in-market & affinity audiences you can just select whatever looks relevant. 

For demographics, you can exclude age ranges, genders and household income just like you can in other campaigns. If you don’t know if you should exclude anything here then just run the default which is targeting all. The bidding algorithm should learn overtime which demographics are driving the best results anyways.

For the listing group be sure only the products you’re wanting to advertise for that asset group are selected. By default it’s always set to advertise “all products” which you probably don’t want to do. There may be a situation where you want to just advertise all products in one asset group if say your store only offers one category of products.

For conversion tracking, make sure you’re feeding it actual sales conversion data and not add to cart or product view conversion data.

Finally, after you have your Pmax campaign set up, you can put together a Pmax Google Ad Experiment to test a different set of assets and signals.