Why do some articles from my website with small Discover audiences not appear in your data?

Our panel comprises consenting users, such as the 40,000 in California, representing a population of 39 million. This means each user represents approximately 975 residents. Then an article seen by, say, 20,000 users on Discover is only be viewed by 21 of our panelists, which is minimal. Due to the limitations of statistical theory and increasing margins of error, we set a visibility threshold for articles.
Articles below this threshold are not displayed in our dashboard, not because they are unseen by our monitor, but because the data available does not allow for a reliable calculation of their score. Our algorithm determines this threshold based on the number of times an article is displayed to our users and its click-through rate (CTR). As the Score is fundamentally a product of its display frequency and CTR, an article may require more displays if the CTR deviates significantly from the average.