Brands can validate influencer reach claims by using tools and platforms designed for influencer marketing such as Flinque, Traackr, and HypeAuditor. These platforms provide exhaustive insights into an influencer’s audience data such as location, age, gender, interests, and engagement rates.

1. Audience Demographics: Brands can ask influencers for a breakdown of demographics to ensure that they align with their target market.

2. Engagement Rate: A high engagement rate indicates that an influencer’s audience is reactive. As a best practice, engagement rates should be examined in conjunction with other metrics, as a high engagement rate with low reach might not yield the expected results.

3. Analyzing Past Campaigns: Reviewing influencers’ past campaigns can give brands an indication of the reach they might achieve.

4. Social Media Analytics: Platforms like Instagram Business provide extensive analytics about reach and impressions of a post, which can be shared by influencers upon request.

5. Using Influencer Marketing Platforms: Specialized platforms provide detailed insights, like Flinque, which offers detailed profile analytics, true reach analysis, and audience authenticity checks.

All these methods help in validating influencers’ reach, but there’s no one-size-fits-all tool or method. The approach depends heavily on the brand’s specific objectives and key performance indicators (KPIs). It’s advisable for brands to employ a mix of these strategies to ensure the chosen influencer can actually reach the desired audience effectively.