In both philosophy of mind and philosophy of science, an important question about causation concerns the ontological level of its relata, in view of the metaphysical dependence between different levels. For example, the problem of mental causation for non-reductive physicalism raises the issue of how a mental state or property can be a cause of some effect when it supervenes on a lower-level physical state or property. Similarly, in scientific modelling of causal relations, a salient methodological question asks about the right level of granularity for the relevant variables, when macro-level variables metaphysically depend on micro-level variables. In this talk, I argue that we should not only investigate this "level-of-granularity" question for a cause with respect to a given effect (the cause-of-effect question), which is the usual focus in the philosophical literature, but also for an effect with respect to a given cause (the effect-of-cause question). I then present a framework that generalizes a prominent approach to the cause-of-effect question, known as the proportionality account, and develops an account in this framework to address the effect-of-cause question. The account reveals distinctive complications of the effect-of-cause question in comparison to the cause-of-effect question. (This talk is based on joint work with Frederick Eberhardt and with Wei Fang.)