And that is why you need to speed up your site!

Today I read a great presentation from Joshua Bixby (Strangeloop). He showed a nice way to create a business case for Web Performance Optimization (#wpo). The case is that a slower user experience leads to less revenue, but it's not easy to prove that. What you could do is set up an A/B test with a slower page as B variant. The upside is that you can make a business case, the downside is that you will lose revenue. Joshua came up with another option: we already have the connection speed and browser version in Google Analytics!

The older browsers and slower connection types have a negative impact on page load times. So they should show us numbers for people with a slower user experience.

I created a spreadsheet and downloaded the data from lots of clients into this sheet. I segmented them by connection type and browser and calculated the average revenue per visitor. These numbers are based on 206.778.873 visits that did €4.540.594.926,86 on revenue. That makes an average of €4.97 per visit.

The browsers

We all know that Internet Explorer has 3 versions that have improved a lot in time: IE6, IE7 and IE8. And all three of them are still responsible for a lot of visits, although IE6 is losing fast lately. I created three groups and the results are:

Amazing isn't it? The value per visit goes from €3,59 to €5,45 (a 50% improvement). So please force your customers to update their browsers so they are willing to spend more....or do we have to speed up our sites 😉

The connections

The connection speed is also a major factor in the user experience. A slow dialup connection doesn't make you happy when surfing around a shop that has uncompressed 8MB images online to show their products. Let's see if this is also represented in the numbers:

The difference is not as big as the browsers show, but there's still enough impact.

Both combined

I combined both browsers and connections so see if for example IE6 + Dialup would be the worst performing couple, and yes:

From left to right the browsers and connections in the order as you would expect. Especially IE6 has a big impact on the numbers, but dialup is not te be ignored also.

And now?

You have the data.
You can calculate the numbers.
You can create a business case.
Start optimizing your site!

The load time of your pages has impact on SEO, AdWords Quality Score, the conversion percentage, server load, pages-per-visit, etc, etc. You can't afford to have a slow site.

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17 thoughts on “And that is why you need to speed up your site!

  1. I assume you're intentionally overlooking the obvious connection between slower connections, older browsers and less disposable income, but I agree that randomly slowing down the site to measure how many sales you lose is ridiculous.

    Could you use the natural (and unbiased) slowdown that comes from peak activity? Do your times change enough when the servers are under load to measure that?

    1. Yes, I'm overlooking that intentionally. My guess is that with all those free updates for browsers income is not an issue. Only connection speed could be income-dependent.

      Great suggestion, but than you would need to have access to server load information and revenue per hour. It's a lot harder to make a business case that way, only to tell the same 😉

      1. Another bias:
        Older browsers often tend to be installed in company networks, and quite a few people use their work-time to do online shopping. Except for the actual purchase that is - that they'll do from their home (on a modern browser).

        1. True, but it also happens the other way around: people search at home where they have time and do the actual sale during lunchbreak at work. It's difficult to see how this is affecting data. The "service provider" report doesn't give enough info to check this.

  2. What about the correlation between older browsers and people using the internet in their office? Is it fair to assume that people are inclined to spend less money online from their workplaces than from their homes?

    1. W3TC is a start, but you also need a CDN, some image combining (CSS sprites), image optimization (Smush-It), script combining, etc 😉

  3. I think that people who use newer browsers and faster connections are more likely to buy something on the internet simply because they are more into it (the internet). You know, only my mum browses with IE6 😀

  4. I did a small new investigation with a segment that only returns visits that started after 6 o'clock in the afternoon. That leaves out most of the schools, offices, etc. And the graph still looks the same. I don't think the other factors play a huge role.

  5. Nice piece of 'research'. I indeed also noticed in Analytics that visitors with older browsers generate less revenue per visit. The Site Speed function in the new Analytics should give us another way to measure effects of page speed. For now the measurement methods are only supported by a small set of browsers, but let's hope it starts generating valuable data in the near future.

  6. You've wonderfully written the post. I've liked your way of penning this. Thanks for sharing this.

  7. Your re-search is really useful.
    Older browsers generate low revenue per visit and the weather also impacts for selling products.

  8. Thanks for this post Andre. And yeah, people visiting your site with old browsers can be frustrating, but it's not always their choice (a lot of corporations still force people to use very updated browsers.

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