Agency wants to install Google Tag Manager alongside analytics — do we actually need both?

On WordPress, if you add Tag Manager without removing the old tracking snippet from header.php or your theme settings, duplicate tracking is guaranteed. Have the dev delete the old code and just add the container snippet. Setting up your analytics measurement ID as a single base configuration tag inside Tag Manager covers everything you need.

If the agency isn't planning to set up search ads or professional network pixels down the road, Tag Manager isn't strictly necessary just to track form submissions. The enhanced measurement feature built right into the analytics tool can already capture basic form submissions without custom code. Sometimes agencies just add an extra layer for their own convenience.

Follow three fundamental rules during the migration: 1) Completely remove the old tracking script from the site. 2) Create the Tag Manager account under your architecture firm's name and grant user permissions to the agency. 3) Test the tags in preview mode before going live to verify that form submissions only generate a single data entry.

Don't pit your developer against the agency. Tell the developer "Just add the Tag Manager code to the site delete the old analytics code, and don't worry about the rest." Then instruct the agency "You will manage all tracking through the tag panel." That way your developer won't have to write code for every single small request.

we forgot to delete the old code two years ago and celebrated because our pageviews doubled overnight. i mean then we realized we were just fooling ourselves and the data was completely ruined... seriously, don't give the green light to the agency until your developer cleans up the old code.

Correction: I misremembered the figure, it was a bit lower.

it's totally normal for agencies to want tag manager, they don't wanna wait on a dev for every single button click. tbh don't worry about site speed either, a properly set up single container won't slow down the site noticeably.

If we delete the old code and reconnect through Tag Manager, will we lose our past months' visitor data and historical reports in the analytics dashboard?

Since you operate in the UK market, I recommend paying close attention to data privacy compliance. It is a legal requirement that any third-party tracking tags deployed via Tag Manager integrate with your site's cookie consent mechanism and do not fire without user consent.

I'm curious too. Don't trust anyone who gives guarantees; there are no guarantees in this business.

Correct me if I'm wrong.

Looking at it as a process, the picture changes. When making a decision, first look at what data you have on hand.

Of course, it varies if your situation is different.

The answer above hits the nail on the head. Hasty decisions become decisions you have to fix six months later.

That's all, sorry if I went on too long.

thanks a lot I'll try it today and updating an existing page yields faster results than creating a new one.

of course it varies if your situation is different.

I partly agree, partly disagree. Don't hesitate to ask; those who don't ask always pay more.

If I were you, I'd go this route.

Im curious too.

We experienced almost the exact same thing last year. If it's your first time, start small; scaling comes later.

Good luck with that.

Here's how it went for us. Merge instead of deleting; deleted content doesn't come back.

If I were you, I'd go this route.

We've heard this a lot, but it never happened like that for us. Any comment made without a control group is just a guess.

If you get three different answers on a topic, the question was asked wrong. Correct me if I'm wrong.

im writing this so you dont make the same mistake but everyone rushing into difference between tag manager and analytics gets stuck at the same point.

if I were you I'd go this route.