Tag Archives: ppc

Setting an optimal bid price for Google CPA bids

A couple of years ago I wrote up the results of an experiment comparing Cost Per Action vs Cost Per Click bidding in Google Adwords. At the end of the experiment I decided that I did trust Google CPA bidding, but the results from CPA bidding weren’t compelling enough for me to switch. So I stayed with my mature CPC campaign. Subsequently I spoke at length with Adwords guru David Rothwell and Adwords master practitioner Alwin Hoogerdijk. They convinced me that:

  • I hadn’t really given Google CPA enough learning time – the more data Google has the better it should be able to do. The mighty Google brain might even be able to spot and exploit patterns I would find very difficult to emulate (e.g. based on season, country, day or week or time of day).
  • I should switch from paying per sale to paying per download, as this would give Google an order of magnitude more data to work with.
  • CPA bidding would require a lot less of my precious time to manage.

So I switched back to CPA. This time measuring a conversion as a successful download and install (my table planner shows a help page in a browser on first run, this contains the Google conversion tracking script).

So now, instead of having to choose thousands of bid prices (one for each keyword and match type in each campaign), I had to choose a single bid price – what I am prepared to pay Google for a download. If I pay too little for a download: Google won’t show my ads much, I won’t make many sales and my profit will be low. If I pay too much for a download: Google will show my ads a lot, but the amount I pay for each conversion will be high and my profit will be low. In between their should be a ‘sweet spot’ that gives me optimal profit. But how to find that sweet spot?

Looking at analytics data I have a good idea at what rate Adwords traffic converts to sales. I chose a CPA bid based on this and then I randomly varied the bid up or down every 7 days (some days of the week perform consistently better than others for my product). The graphs below show the results. Each data point is 7 days of data. The black lines are linear trend lines. I deliberately haven’t put values on the axes, but the x and y axes are all linear, starting at 0.

The trends are pretty clear. Increasing CPA bid price:

  • increases the number of times your ads are shown
  • makes little difference to the click through rates
  • decreases the click to download and download to sale ratios

So higher bids means more sales, but also a higher cost per sale. But, of course, the really important metric is profit. So I worked out the average daily profit from Adwords traffic, which is the net sales income (gross sales minus sales costs, including payment processor fees and support costs) minus Adwords costs. Again each point is 7 days of data. The black line is a 2nd order polynomial trend line.

The data is quite noisy. But some data is a lot better than none and there does appear to be sweet spot about where the red arrow is. The curve is fairly flat meaning that I don’t have to be too precise in my bid price to get a near to optimal return. But if I bid twice the optimal price my profit will drop by about 35%.

In an ideal world I would have run all these different bid prices concurrently, instead of one after the other. But that just isn’t possible with Adwords at present (you can use Google Adwords experiments to split test bid prices, but only 2 at a time). Also I could have gathered a lot more data, used longer time intervals (7 days probably isn’t long enough for Google CPA to get into its stride) and bid a lot higher and lower, to make the trends clearer. But I wasn’t prepared to spend the extra time and money required.

If you are using CPA bidding you should be able to carry out a similar analysis on your own Adwords account to find your own CPA bidding sweet spot. If you are still using CPC, perhaps you should consider switching to CPA and let Google do some of the heavy lifting for you. You can switch any campaign that has 15 or more conversions per month to CPA bidding in the ‘Settings’ tab.

You can always switch back to CPC later. If you aren’t using Google conversion tracking, well you really should be.

A word of warning. Not all downloads are equal. You might think that download to sale rates would vary a lot less than impression to click and click to download rates (I did). But download to sale ratios can vary a lot between different campaigns, even for the same product. For example, my analytics data shows that downloads from Adwords display (=contents/adsense) traffic only convert to sales at around a quarter of the rate of Adwords search traffic. So display campaign downloads are worth a lot less to me than search campaign downloads and I set my CPA bids accordingly.

I showed a draft version of this post to Alwin Hoogerdijk of Collectorz.com collection database software, who first persuaded me to switch back to CPA and knows a lot more about CPA than I do. He had the following to add:

When using CPA bidding you should give Google more room to experiment. On search, this means using more broad match terms, or at least modified broad match. And less negative keywords (I removed a lot of my negatives lately). The idea is that Google will automatically find out what works and what doesn’t (again, this may take a lot of time).

On the Content Network it means being less trigger-happy with the site exclusions. Without CPA bidding, I would be more likely to exclude generic sites like Facebook, about.com, etc… But with CPA bidding, I tend to allow the optimizer to display on those sites and the find the right pages within those sites to show my ads on.

In my experience, the optimal CPA bid can vary (wildly) between products, campaigns, etc. . Content Network CPA’s in general tend to be much lower, for the same products. Strangely enough, content network visitor sign up (or downloads) are worth less than search traffic sign ups. Which wasn’t what I was expecting. Of course, content network traffic is less targeted in general so one would expect a lower sign up rate. But even if those visitors sign up, they convert less well to actual sales too. Tricky.

Is it worth advertising Mac software on Google Adwords?

I learnt a long time ago that people will happily click on totally irrelevant pay per click ads. For example, if you bid on “seating plan” I can assure you that a significant percentage of people searching for “boeing 747 seating plan” will happily click on your ad titled “wedding seating plan”. They won’t buy anything, as they aren’t interested in wedding seating plans, but you still have to pay for each click. You can stop your ad showing to these searchers by adding “boeing” and “747” as negative keywords. Problem solved.

But what do you do if you are selling software that only runs on Mac OS X? The vast majority of searchers are running Windows. Indiscriminate clicks by them could quickly turn your Adwords ROI negative. In your Adwords campaign settings you can choose to only show ads on desktop computers and laptops. But you can’t choose the operating system.

As discussed above, putting “Mac” in the title is unlikely to be enough. You can’t use negative keywords, because the vast majority of Windows users searching for, say, backup software will type “backup software” not “Windows backup software”. You can just bid on searches containing keywords “Mac”, “Apple” or “OS X”, but will this be enough? My general advice to Mac only software vendors was to avoid Adwords, unless the ticket price of their software was in the hundreds of dollars. But, as my software runs on both Windows and Mac, I didn’t have any data to back this up.

Recently I got some data on Adwords clickthrough rates for a Mac only app (www.puzzlemakermac.com) by Hokua Software. They have kindly allowed me to share the data.

Initially they bid on generic keywords, such as “crossword maker” and ran ads such as the following with “Mac” displayed prominently in the title:

The results from analytics: 60% of the people clicking on the ads were on Windows and 40% on Mac.

Then Google banned them from the word “Mac” in their ads (it is possible to get this reversed with the express permission of Apple, but I don’t know how likely they are to grant this). So they switched to “OS X” in the ad, which hasn’t been blocked (yet).

The results from analytics: 73% of the people clicking on the ads were on Windows and 27% on Mac.

Then they restricted their bids to Mac targeted keywords such as “mac crossword maker”.

The results from analytics: 23% of the people clicking on the ads were on Windows and 73% on Mac. But there was a big drop in the number of impressions.

I think it is going to be almost impossible for anyone to get a return from Adwords when the majority of their clicks have no chance of generating a sale. So only bidding on Mac specific keywords seems to be the way to go. But there will still be a significant number of wasted clicks from Windows users. Also any Mac users who don’t use the appropriate keywords won’t see your ad. Consequently the return on time and money invested is likely to be a lot lower than Windows, cross-platform and web developers can expect. If you have a Mac only product with: a high ticket price product, well-defined keywords and limited competition, it might be worth trying Adwords. But otherwise it is probably better to wait and see if Google release OS targeting.

Of course, you could always use one of the free Adwords vouchers that Google are handing out like confetti (I get one every month in my PC Pro magazine) and try for yourself. This is how Hokua software got the results above. If you do, I would be interested to know how your results compare.

A small experiment with LinkedIn ads

LinkedIn.com (the B2B equivalent of Facebook) supports Google style pay per click ads. So I decided to run some ads for my seating planner software as an experiment. Here is a brief summary of my (very brief) experiences.

The good news

LinkedIn ads can be laser targeted. You can specify who you want to see your ad based on their job function, company, gender, age group, country and (best of all) the LinkedIn groups they belong to. I targeted 10,102 LinkedIn members who live in wealthy English speaking countries, belong to various LinkedIn groups related to event planning and have appropriate job titles. The campaign was quite painless to set up. It probably took me less than 10 minutes in total and I started getting impressions within an hour or so.

The bad news

The minimum allowed CPC (cost per click) was $2. Ouch. I know from extensive experience with Google Adwords that there is no way I can get a return on that.

The minimum allow CPM (cost per thousand impressions) was $3. If the CTR (click through rate) is around 1% (about what you might expect from Google search ads) this is $0.30 per click. Possibly profitable. If the CTR is around 0.1% (about what you might expect from Facebook ads) this is $3 per click. No better than the CPC bidding. Given that LinkedIn is more similar to Facebook than Google search, I expected the latter. I decided to spend a few dollars to find out. The results are below (click to enlarge):

So, with an average 0.17% CTR, I ended up spending $1.76 per click. Given my average transaction value and a realistic conversion rate I know that I can’t make any return on this. Also the CTR is likely to drop the more often people see the ad. So I stopped the experiment after less than 24 hours, before I wasted any more time or money. As far as I can tell (based on my own cookie tracking – LinkedIn ads don’t have their own conversion tracking) I didn’t make any sales. But that is hardly surprising given the small number of clicks.


Obviously $19.38 is a tiny amount to spend, but I think it told me what I needed to know about LinkedIn ads. Unless they reduce their CPC or CPM bid prices by an order of magnitude there is no way I can make a return. Of course, if you are selling a product where the average lifetime value of a customer is hundreds or thousands of dollars, the numbers might work out quite differently for you.

Related posts:

Advertising your software on Facebook (=Fail)

Advertising your software on Facebook (=Fail)

Facebook previously didn’t allow the advertising of downloadable software. Someone told me that they had relaxed this policy, so I checked their guidelines. Sure enough they have removed the offending line in their guidelines that used to say:

No ad is permitted to contain or link, whether directly or indirectly, to a site that contains software downloads, freeware, or shareware.

It says in their guidelines that downloadable software that does naughty things such as “sneaks onto a user’s system and performs activities hidden to the user” is not allowed, which is fair enough (see section 14 of their ad guidelines for the details).

Woohoo! As part of my ongoing project to try every legitimate form of promotion known to man, I can try advertising my seating planner software to, for example:

I ran 5 different ads over a couple of weeks. For example:

advertising software on facebookTrying to fit an attention grabbing and informative ad into the very limited strapline and image size was challenging. But I didn’t spend too long agonizing over the ‘creative’ (image and text), as this was just a feasibility study. The biggest problem was the minimum bid prices. Facebook was recommending I bid at least £0.40 per click. Given that the majority of my customers buy a single licence for £19.95 and typical conversion rates for clicks are around 1%, I would be likely to lose money if I bid £0.20 or more (especially when you consider ecommerce fees and support). I bid £0.10, but got no impressions at all. I bid £0.20 as an experiment and got a reasonable number of impressions. As soon as I dropped the bid to £0.15 the impressions slowed to a trickle.

Here are the stats from my experiments, as reported by Facebook:

Impressions: 357,366
Clicks: 310
Click through rate: 0.087%
Total cost: £46.60
Average cost per click: £0.15
Average cost per 1000 impressions: £0.13

Any of you who are used to Google Adwords might be surprised how low the CTR is. But apparently this is quite a reasonable CTR for Facebook. This isn’t too surprising when you consider that people are on Facebook to socialise, rather than to search for stuff.

Of course, the most important metric is the profit. So how many licences did I sell? According to my own cookie tracking: zero. Zilch, nada, nothing, not one. Cookie tracking isn’t 100% reliable, but it seems that a 1% conversion rate might be highly optimistic for a facebook ad. Advertising a £19.95 product on Facebook to people who might be planning to get married obviously wasn’t going to be profitable given my price point, the minimum bid prices and low conversion rate. So I created a new ad to try to target a more focussed demographic, who might convert better and perhaps buy one of the more expensive versions of my product. Ad number 6 was disallowed one minute after it had been approved.

Eh? This ad was very similar to the previous 5 approved ads and for the same product. Their email said:

The content advertised by this ad is restricted per section 5 of Facebook’s Advertising Guidelines. Restricted content includes, but is not limited to: 1. Downloadable products that may affect the user’s computer or browser performance in unexpected or undesirable ways; 2. Get rich quick and other money making opportunities that offer compensation for little or no investment, including “work from home” opportunities positioned as alternatives to part-time or full-time employment or promises of monetary gain with no strings attached. 3. “Free” offers that require users to complete several hidden steps or make additional purchases in order to receive the promised product. We reserve the right to determine what advertising we accept, and will not allow the creation of any further Facebook Ads of this type. Ads for this product, service or site should not be resubmitted.

I didn’t feel my ad/product violated any of those criteria. It was clear in the ad that only the trial was free (not the product) and it doesn’t do anything nasty or sneaky. I emailed them for clarification. Here is the response:

Hi Andy,

Thanks for your email. Please note that we don’t accept ads for downloadable products through our self-service advertising channel. We reserve the right to determine what advertising we accept, and will not allow the creation of any further Facebook Ads for this product.

In order to maintain legitimacy of the products and services promoted on Facebook, ads for downloadable or installable products are only permitted through a direct sales partnership with Facebook. At this time, we’re only able to provide this service to a small set of qualified advertisers.

We’re committed to providing high-quality support for all of our advertisers, and we’ll keep you and your business in mind for the future growth of our ads product. In the meantime, please continue to email us here with any questions you may have and we’ll be happy to answer them for you.

If you have any further questions about why your ad was disapproved for Restricted Content, please refer to our Help Center about downloads at:




Online Sales Operations


So apparently, they still don’t accept advertising for downloadable software, unless you are an approved partner, because it ‘may affect the user’s computer’ (even if it doesn’t ). This wasn’t at all clear in their guidelines and they let me run 5 ads before they enforced it (these ads are still running BTW). Thanks Facebook, I like you less with every passing day (and I didn’t like you much to start with). At least I got enough data to show that I was unlikely to ever get a return on advertising a £20/$30 product. I also console myself with the fact that PerfectTablePlan is doing better financially than Facebook (after 7 years and with 500 million users Facebook are finally cash flow positive, but nowhere near recouping the estimated one billion dollars in venture capital) and my product will hopefully still be selling profitably after Facebook has  been buried by the ‘next great thing’ that comes along so regularly in the world of social media.

Yahoo can modify your PPC campaign without your permission

I tried Yahoo pay-per-click a few years ago, but gave up due to low traffic, high minimum bid prices and a horrible user interface. I am glad I did. Apparently Yahoo Search Marketing have given themselves permission to:

  • create ads
  • add and/or remove keywords
  • optimize your account(s)

for US advertisers, without asking their permission first. One can only wonder what ‘optimize’ means – double your bid price? You can revert their changes, but you are still liable for any costs their changes incur. Isn’t this a bit like the phone company deciding you aren’t making enough calls and phoning people on your behalf? There doesn’t even appear to be an opt-out. Yahoo must be getting pretty desperate. Let’s hope they are better at picking new keywords than Microsoft Advertising.

More details here:

If you have a Yahoo PPC campaign you might want to think about cancelling it. Or at least keep a very close eye on it. If you have actually experienced Yahoo making changes to your campaigns please post details in the comments.

(via Adriana Iordan of Avanagate)

Unlock new customers?

Microsoft Adcenter helpfully sent me a link to lists of low cost keywords I could advertise on, categorised by sector, to “unlock new customers”. I had a quick look through the ‘sport and rec’ list. Here is a small sample (click to enlarge):

There are lots more where they came from. Microsoft say:

These keywords are actual terms recently used by your customers on Live and MSN Search Engines and are available at a low cost while very few other advertisers are bidding on them.

No kidding.

Did they do any QA on this list[1]? Exactly how many people are searching on “vn b m gn mbnmncbm xbc bcv 0 vfkmjirhtfnkj nb b x bmnx bv”? What has dogging (not work safe) or Hare Krishna got to do with rugby? Is it any wonder nobody is bidding on “duck porn”? Are there really that many people interested in pictures of nude female bodybuilders (apparently)?

Thanks Microsoft, but I’m really not sure they are the sort of new customers I want to unlock.

[1]There are some pretty unpleasant ones I didn’t include.

Microsoft adCenter over reporting conversions

I have long suspected that Microsoft adCenter is over reporting conversions. Here is the confirmation from my adCenter reporting:

I am guessing that the purchaser visited the ‘thank you for your purchase’ page (which contains the conversion tracking script) 5 times, for whatever reason. I can’t think of any other way this situation could occur – the conversion tracking isn’t set up to take account of multiple purchases in one transaction. How difficult would it be to only count the first visit? Google can do it.

Being cynical, perhaps the over reporting suits Microsoft? But it makes it much more difficult for me to assess the real effectiveness of keywords and ads. Another good reason to concentrate my efforts on Google Adwords instead.

Google Adwords: improving your ads

google adwordsOne of the keys to success in Google Adwords (and other pay per click services) is to write good ad copy. This isn’t easy as the ads have a very restrictive format, reminiscent of a haiku:

  • 25 character title
  • 2×35 character description lines
  • 35 character display url

Whats more, there are all sorts of rules about punctuation, capitalisation, trademarks etc. You will soon find out about these when you write ads. Most transgressions are flagged immediately by Google algorithms, others are picked up within a few days by Google staff (what a fun job that must be).

Google determines the order in which ads appear in their results using a secret algorithm based on how much you bid, how frequently people click your ads and possibly other factors, such as how long people spend on your site after clicking. Nobody really knows apart from Google, and they aren’t saying. The higher your click frequency, generally the higher your ad will appear. The higher your ad appears in the results, generally the more clicks you will get. So writing relevant ads is very important. This means that each adgroup should have a tightly clustered group of keywords and the ads should be closely targeted to those keywords.

There is no point paying for clicks from people who aren’t interested in your product, so you need to clearly describe what you are offering in the few words available. For example you might want to have a title “anti-virus software” instead of “anti-virus products” to ensure you aren’t paying for useless clicks from people looking for anti-viral drugs (setting “drugs” as a negative keyword would also help here).

I have separate campaigns for separate geographic areas. Each campaign contains the same keywords in the same adgroups, but with potentially different bid prices and ads. This allows me to customise the bid prices and ads for the different geographic areas. For example I can quote the £ price in a UK ad and the $ price in a US ad. Having separate campaigns for separate geographic areas is a hassle, but it is manageable, especially using Google Adwords editor.

Writing landing pages specific to each adgroup can also help to increase your conversion rate. It is worth noting that the ad destination url doesn’t have to match the display url. For example you could have a destination url of “http://www.myapp.com/html/landingpage1.html?ad_id=123” and a display url of “www.myapp.com/freetrial”.

Obviously what makes for good ad copy varies hugely with your market. Here are some things to try:

  • a call to action (e.g. “try it now!”)
  • adding/removing the price
  • different capitalisation and punctuation
  • keyword insertion (much beloved of EBay)
  • changing the destination url

But, as always, the only way to find out what really works is testing. Google have made this pretty easy with support for conversion tracking and detailed reporting. I run at least 2 ads in each adgroup and usually more. Over time I continually kill-off under-performing ads and try new ones. Often the new ads will be created by slight variations on successful ads (e.g. changing punctuation or a word) or splicing two successful ads together (e.g. the title from one and the body from another). This evolutionary approach (familiar to anyone that has written a genetic algorithm) gradually increases the ‘fitness’ of the ads. But you need to decide how to measure this fitness. Often it is obvious that one ad is performing better than another. But sometimes it can be harder to make a judgment. If you have an ad with a 5% click-through rate (CTR) and 0.5% conversion rate is this better than an ad with a 1% click-through rate and a 2% conversion rate? One might think so ( 5*0.5 > 1*2 ) but this is not necessarily the case. I think the key measure of how good an ad is comes from how much it earns you for each impression your keywords get.

I measure the fitness by a simple metric ‘profit per thousand impressions’ (PPKI) where, for a given time period:

PPKI = ( ( V * N ) – C ) / ( I / 1000 )

V = value of a conversion (e.g. product sale price)

N = number of conversions (e.g. product sales) from the ad

C = total cost of clicks for the ad

I = impressions for the ad

Say your product sells for $30. Over a given period you have 2 ads in the same adgroup that each get 40k impressions and clicks cost  an average of $0.10 per click.

  • ad1 has a CTR of 5%, a conversion rate of 0.5% and gets 10 conversions, which gives PPKI=$2.5 per thousand impressions
  • ad2 has a CTR of 1%, a conversion ratio of 2% and gets 8 conversions, which gives PPKI=$5 per thousand impressions

So ad2 made, on average, twice the profit per impression despite the lower number of conversions. Given this data I would replace ad1 with a new ad. Either a completely new ad or a variant of ad2.

PPKI has the advantage of being quantitative and simple to calculate. You can just export your Google Adwords ‘Ad Performance’ reports to Excel and add a PPKI column. Some points to bear in mind:

  • Selling software isn’t free. You may want to subtract the cost of support, CD printing & postage, ecommerce fees, VAT etc from the sale price to give a more accurate figure for the conversion value.
  • PPKI doesn’t take account of the mysterious subtleties of Google’s ‘quality score’. For example an ad with low CTR and high conversion rate might conceivably have a good PPKI but a poor quality score. This could result in further decreases in CTR over time (as the average position of the ad drops) and rises in minimum bid prices for keywords.
  • PPKI is a simple metric I have dreamt up, I have no idea if anyone else uses it. But I believe it is a better metric than cost per conversion, or any of the other standard Google metrics.

To ensure that all your ads get shown evenly select ‘Rotate: Show ads more evenly’ in your Adwords campaign settings. If you leave it at the default ‘ Optimize: Show better-performing ads more often’ Google will choose which ads show most often. Given a choice between showing the ads that make you most money and the ads which make Google most money, which do you think Google will choose?

Text ads aren’t the only type of ads. Google also offer other types of ads, including image and video ads. I experimented with image ads a few years ago, but they got very few impressions and didn’t seem worth the effort at the time. I may experiment with video ads in the future.

The effectiveness of ads can vary greatly. Back in mid-December I challenged some Business Of Software forum regulars to ‘pimp my adwords’ with a friendly competition to see who could write the best new ads for my own Google Adwords marketing. The intention was to inject some fresh ‘genes’ into my ad population while providing the participants with some useful feedback on what worked best. Although it is early days, the results have already proved interesting (click the image for an enlargement):

adwords ad results

The graph above shows the CTR v conversion ratio of 2 adgroups, each running in both USA and UK campaigns. Each blue point is an ad. The ads, keywords and bid prices for each ad group are very similar in each country (any prices in the ads reflect the local currency for the campaign). Points to note:

  • There were enough clicks for the CTR to be statistically significant, but not for the conversion rate (yet).
  • The CTRs vary considerably within the same campaign+adgroup. Often by factor of more than 3.
  • Adgroup 1 performs much better in the USA than in the UK. The opposite is true for adgroup 2.
  • Adgroup 1 for the USA shows an inverse correlation between CTR and conversion rate. I often find this is the case – more specific ads mean lower CTR but higher conversion rates and higher profits.

‘Pimp my adwords’ will continue for a few more months before I declare a winner. I will be reporting back on the results in more detail and announcing the winner in a future post. Stay tuned.