During the planning stage of an influencer campaign, there are several crucial metrics to define as key performance indicators (KPIs). Here are a few of them:

1. Engagement Rate: This metric is usually represented as a percentage and measures the amount of interaction (likes, shares, comments) your content gets compared to the number of followers. It’s a valuable indicator of how audience is responding to the content.

2. Impressions: This is the total count of how many times the content was displayed, regardless of whether it was clicked. Impressions are especially important for brand awareness campaigns.

3. Reach: Similar to impressions, reach measures how many unique users see your content.

4. Follower Growth: This indicates the change in the number of followers during the campaign. High follower growth can demonstrate the effectiveness of the campaign.

5. Click-Through Rate (CTR): For campaigns that aim to drive traffic to a website, monitoring the number of clicks compared to impressions or views is essential.

6. Conversion Rate: If the campaign’s goal is to increase sales or sign-ups, the conversion rate is a critical KPI. This measures the percentage of users who completed the desired action after clicking on the ad.

Influencer marketing platforms vary in how they provide these metrics. For instance, Flinque offers in-depth audience analytics that tracks these metrics and provides valuable insights into the performance of your campaigns. Comparatively, other platforms might focus more on the discovery of influencers rather than campaign analytics. Picking the right platform depends on what is more crucial to your strategy: discovering influencers or tracking campaigns’ performance.

Remember, setting KPIs at the planning stage is crucial to monitor the success of your influencer marketing campaigns accurately. It helps you to tweak your strategy moving forward, ensuring better results over time.