Measuring campaigns by repeat purchases and margin

A campaign can generate many clicks and still fail to produce useful repeat business. Before launching it, decide which behaviour you want to change and how you will tell whether the offer contributed to that change.

Define the result and the time window

For a second-purchase campaign, count customers who complete another qualifying purchase within an agreed period after the first. Keep the denominator clear: all eligible customers, or only those selected for the campaign. Use the same definition when comparing results.

Match the period to the buying cycle. A weekly service and a durable product need different observation windows. Exclude cancelled orders consistently and decide how returns affect the result.

Connect visits to completed orders

Campaign links can help identify where traffic comes from. Google’s campaign URL guidance explains parameters such as utm_source, utm_medium and utm_campaign. Use consistent naming and avoid putting customer names or email addresses into URLs.

Combine traffic reporting with order and campaign records. A redeemed code records use of the offer; it does not establish that the customer would not have purchased without it. Shared codes and purchases completed through another channel can also complicate attribution.

Count the cost of the benefit

Use net sales after discounts and returns as a starting point, then consider product cost, payment fees, delivery support and other relevant variable costs. Review advertising and the cost of delivering the reward as well. Keep the calculation consistent and avoid counting the discount twice when sales are already recorded net of it.

Where practical, compare randomly selected similar groups with and without the offer. Small samples and changes in season or availability can make conclusions uncertain, so avoid treating one successful week as a permanent effect.

A concise report can show eligible customers, returning purchasers, net sales, campaign costs and customer feedback. Use it to decide whether to repeat, change or stop the campaign. The aim is a sustainable reason for customers to return, supported by results the business can understand.