Apple files every app into one primary category, and each category has its own charts. We track free, paid and top-grossing charts across all of them.
Categories differ enormously in how much they move. In some, the top hundred turns over constantly and a new app can appear within weeks; in others, the same apps have held position for years. A report tells you which kind yours is.
This is why the same idea can be a reasonable bet in one category and hopeless in another — it is often the single biggest factor and the one people account for least.