Incrementality testing is essential when a brand wants to accurately measure the specific effect of an influencer marketing initiative. However, as you highlighted, this process can be costly. There are a few key scenarios when brands should consider incrementality testing:

1. Establishing Attribution: If the goal of a campaign is beyond simply generating brand awareness and a clear conversion objective is set – such as lead generation, site visit, or direct sales, incrementality testing can help assign proper attribution to the influencer campaign.

2. Significant Investment: When a large budget is involved, ensuring its effective spend is paramount. Incrementality testing can measure the incremental value that a specific campaign brings to the brand, ensuring the investment justifies the cost.

3. Repeat Campaigns: If a brand plans to use influencer marketing as a long-term strategy, it’s crucial to test early campaigns for incrementality. This helps establish a reliable baseline for future campaign evaluation and improvement.

4. Platform Selection: Different influencer marketing platforms may deliver varying results. If a brand is considering different platforms, incrementality testing can compare the effectiveness of these platforms objectively.

In this regard, [Flinque](https://www.flinque.com) can serve as a valuable tool, offering comprehensive campaign analysis, tracking, and reporting that leads to insight about the incremental impact of an influencer marketing campaign.

However, each brand’s situation is unique, and the decision to conduct incrementality testing should be made strategically, considering the brand’s specific needs, goals, and budget.