Last year we migrated NHS.UK and Public Health England from Sharepoint to Wagtail. Whilst some of our case studies provide a good overview of these projects, we wanted to focus on one of the biggest challenges corporate IT face. Content migration.
With the NHS.UK project, we migrated around 10,000 pages of content for News and Conditions alone. When you are part of an organisation such as the NHS, where your site averages around 50 million visits per month, a migration to a new technology or content store can be daunting. It doesn’t need to be. We’ve developed an approach that works for any technologies at any scale. Helping organisations prioritise their efforts where it matters, user value. Here’s three of the repeatable steps we take to make sure migrations run smoothly.
Focus on the Things That Matter Most
The first and most vital part of any migration effort is truly understanding your site. The best way to tackle any large task is to break it up into achievable chunks. Understanding your site lets you decide what these chunks are and where to focus your team's efforts. We are confident enough to help our clients prioritise their top content areas, the bits that will provide the most value for their users. But equally, if it’s your first migration or you have significant concerns, you may want to run a test on an area of the site that isn’t as critical to the success of your organisation.
Here at VIX, we’ve built tooling that allows us to turn measurements from analytics and search into powerful metrics and key performance indicators (KPIs) for content. We serve these through automated dashboards which will keep providing value well after the migration effort. Having these insights allow us to focus on content that is performing poorly, business critical, and what your users rely on most. You might not have these tools, or the time to build them. But you can still achieve an understanding of your site with a little more time, cost and effort by using an analyst to manually generate these reports. Trust us, it’s worth it.
You have assessed your site, you understand it deeply and you have decided to migrate a section of it. How can you be sure that your efforts are an improvement? This is where your metrics and KPIs will serve you well. We typically test a portion of the traffic against our newly migrated pages and base our decisions around the outcomes. This builds confidence at the highest levels of your organisation, where it really matters.
One of the most important metrics you can share for confidence, is the difference between your source content and the migrated content. As part of your migration effort, you’ll usually migrate the content from your original system into a language-independent data format such as JSON. You will then populate your new data models from this format.
You will want to see how closely your new content matches the existing content. There are many different ways to calculate this depending on the amount of content, speed and accuracy you require. For NHS.UK we used the Levenshtein distance. For a manual migration effort, this might not be a big deal. But for an automated migration at scale, you should be able to tell stakeholders in percentage terms how close the content is to the original.
You also want to be able to highlight any pages which are significantly different, since those pages will provide the best insight into areas the migration methods performs poorly. This allows you to make data driven decision around content, and allows content editors to focus their efforts on the areas where automated migration algorithms may perform poorly.
With services such as NHS.UK, we were dealing with health critical information which people relied on. If we tell a person to take a different dose of their medication, they could be in serious danger. We could not afford to have a clinician review around 6000 pages of conditions content which wasn’t due to be reviewed for another year or two. And this was just one section of the site. Our difference score had to be perfect for us to proceed to the next step.
Turning It Off
You have picked a section of the site. You are confident that the content has been successfully migrated. And you are testing it with users to make sure you are providing a better experience. We usually call this the Beta state. What’s next? Well, it’s not always as simple as turning the old thing off.
Depending on the service, “turning it off” can mean a few different things based on the outcome you are providing. But for the most part, you are attempting to make things better along the way and need to pick a point in time where to make the switch.
Here’s a simple visualisation we find ourselves drawing often. In blue we have the live service traffic. In green we have the beta content traffic. As we migrate a service, we can tweak the amount of traffic sent to either and the curve typically looks like this.
At some point you will want to make the switch. There will be decision makers who want things to be perfect. Teams will argue the migrated service already outperforms the existing one. This is when your KPIs will save you significant cost and time. Opinions cost a lot of money at this stage, you need a reliable metric to aim for.
It’s rare we’re part of a project with a grand reveal. A zero to hundred traffic flip usually doesn’t happen overnight. If you stick to a success metric, your transition period should see you confidently flipping the switch early on. This stage of a project is all about setting expectations. If we meet a target, we will flip the switch.
We have a set of metrics that work well for us and our clients, but the most important thing is to define a metric early on that means success for you and your service. You should continue to refine that metric over time. You might start out with a goal of reducing your bounce rate, only to learn that a high bounce rate on certain areas of content are actually valuable to certain types of services. That is fine. Find out what success looks like and define a metric that you can test throughout this period. Having a shared understanding in the form of a metric, from the start, cuts out all of the opinions. You and your organisation will appreciate it.
There are obviously more than three areas to focus on when migrating content. But these key steps will provide you with a solid foundation for migration at scale. The technology is usually the simplest part, having a team which understand your organisation and culture is where you will make significant gains in terms of cost and time.
This is just a small insight into the hard work that goes into a successful migration. If you would like some more advice, get in touch with us for a chat at firstname.lastname@example.org.