Your website operations team is, at this very moment, engaged in a ruthless battle. It’s fought against a relentless swarm of tiny combatants – the millisecond soldiers in the service of the arch enemy of all website operators, page latency. This fight demands attention at every turn, and is engaged every time another member of the organisation plans to adopt a new marketing or audience measurement technology.

Sophisticated sites battle the latency introduced by third party tags in a variety of ways that involve some combination of dedicating monitoring, optimised content delivery networks, and judicious policies about adding new technology.

These strategies are based on an intuitive, fairly straightforward assumption – the more tags on a page, the higher the impact on latency. For the most part, the data supports this theory.

The loose industry standard for how long a page should load is around 2 seconds, and up to 20 third party tags tends to stay in this latency range. Things progress logically up to about 4 seconds of page load, as the number of tags climb close to 30.

At first glance, it may be surprising that the addition of five tags represents nearly a full second of additionally latency – but this is probably indicative of tags added outside of tag management systems, or tags from inactive marketing initiatives that are mostly forgotten (and thus, unoptimised).

A more surprising correlation occurs when we look beyond 4-second page loads, and find that the number of tags per slower-loading page actually trends lower.

As always, correlation does not imply causation – fewer tags don’t make for a slower page as a rule. But if tags contribute to page latency, why the relationship between high latency and relative tag scarcity? This is likely a result of some combination of a few less obvious realities of the online marketing world.

Slow Pages Mean Less Data

Latency has an ugly effect on all sorts of user engagement statistics, including user flight. Slow-loading content causes users with ever-increasing expectations for instant gratification to immediately click away. This means that lagging tags never execute – resulting in a decrease in collected data about the user, and an apparent decrease in the number of tags on the page. If the code were to execute fully on these pages, their tag counts might be much higher – but testing a user’s patience means missing opportunities to gather data about them.

Marketers Pick Their Partners

Decline in latency-effected statistics like page views, time on page, and user satisfaction has a domino-like effect on ad revenue. Not only does poor performance have a direct impact on conversions, but marketing companies look at site performance as they pick sites with which they’d like to partner. So latency not only impacts the tags already deployed on a site, but limits the potential future partners as well.

Optimisation Is Everything

Many site operators have worked to break the relationship between tag volume and high page latency. Strategic deployment of tag managers and CDNs allow tags to load synchronously, mitigating the impact on total page time. Site technology can also be configured so that certain tags only fire when they’re most useful, and well managed exchange relationships can maximise return from fewer deployed marketing partners. Pages that have not invested in increased performance are also not likely to have taken a performance-related approach to managing their tag partners, either.

Sun Tzu wisely counseled, “Know thyself, know thy enemy. A thousand battles, a thousand victories.” The ancient philosopher was almost certainly not thinking of web page performance, but it’s nonetheless true that a close look at how tags are performing on your site can lead to tactical epiphanies about how they can be better managed. So if you find yourself losing the battle against the ever-persistent horde of milliseconds, you need not concede the war. Join the ranks of the self-reflective sites that have taken steps to refine their technologies, and turn the tide against the relentless forces of time itself.