Hi Tom,
The empirical research that I was thinking about is from "The Divergence of High- and Low-Frequency Estimation: Implications for Performance Measurement," published in Journal of Portfolio Management 41(3):14-21, Spring 2015. Here's the relevant passage:
"We hypothesize that high-frequency variability arises from changes in discount rates, whereas low-frequency variability is caused by differences in cash flows. Changes in discount rates occur relatively often because a constant flow of new information causes investors to reassess the riskiness of a stream of cash flows, which therefore leads to high-frequency variability. In addition, the value of a portfolio or strategy may gradually appreciate or erode over a long horizon, because the drift of cash flows shifts upward or downward as fundamentals change. This process introduces low-frequency variability."