This note examines metrics for target control and source estimation in dynamical networks. Specifically, the energy required to control a target node in a network from a remote input, and dually the fidelity with which a source state can be estimated from a noisy remote measurement, are studied. For both problems, spectral and graph-theoretic analyses are undertaken, and a comparison between the two metrics is also developed. The analyses highlight an essential asymmetry between target control and source estimation. (C) 2018 Elsevier Ltd. All rights reserved.