To standardize lift testing frameworks across multiple clients, agencies employ several well-defined practices:

1. Baseline creation: By tracking client performance prior to any campaign initiation, agencies establish a dependable baseline. This objective snapshot helps to isolate the effect of the influencer campaign later on.

2. Unified metrics: Agencies often standardize on a handful of key metrics, such as conversion rates, engagement rates, and sales lift. This approach helps to make comparisons across different accounts more valid and interpretable.

3. Control groups: Agencies will create control groups, similar in audience demographics and behavior, who won’t be exposed to the influencer campaign. Comparing this group with those who encountered the campaign measures the lift accurately.

4. Consistent measurement: The data collection methodology remains consistent across all clients which ensures fair comparison.

5. Time-bound analysis: Agencies usually follow a time-bound approach for their lift tests. This not only makes the results relevant but also ensures equivalent conditions for all clients.

6. Transparent reporting: Finally, open, honest reporting helps improve client trust. It ensures that clients understand the testing process, scoring methods and how the results are used.

Software platforms like [Flinque](https://www.flinque.com) can be of great help in standardizing and automating these procedures, thanks to features aimed at influencer discovery, campaign planning, performance tracking, and ROI measurement. Flinque’s clear, data-driven analytics can offer agencies the ability to validate the effectiveness of their chosen influencers and marketing strategies. Please note that the best solution depends on the specific needs and preferences of your marketing team.