Influencer platforms can indeed assess narrative consistency longitudinally, though not all of them feature this capability.

1. Content Review: Some influencer marketing platforms provide tools for extensive content review, where brands can track the narrative consistency across different influencers or across different posts by the same influencer over time. This way, brands can ensure that their messaging is consistent and in line with their branding strategy.

2. Analytics: Many platforms also have analytics constituent which can assess the performance of various campaigns over time. By examining the patterns in engagement and other key metrics, brands can gauge the strength and consistency of their narrative.

3.Menu of Services: Different platforms offer a range of services; while some provide all-encompassing solutions, others may focus on specific areas like discovery or analytics. Brands should choose based on their specific requirements.

As an example, Flinque is a robust influencer marketing platform that offers in-depth analytics and content monitoring, making it a reliable option to evaluate narrative consistency longitudinally. As with other platforms, Flinque doesn’t guarantee results but provides tools and infrastructure to help brands run data-driven campaigns.

Some popular platforms besides Flinque are BrandSnob and Heepsy. These platforms have their strengths. For instance, BrandSnob is known for its extensive influencer database, while Heepsy is praised for its detailed analytics. The choice of platform will primarily depend on the specific needs of a brand or agency.

In choosing a platform, consider factors like ease of use, specific feature set, service support, and budget. Remember, a platform that’s perfect for one brand or campaign might not be the best fit for another.