@inproceedings{2173edf7ca7d44c68c60ae0432f261c1,
title = "Log-normality and skewness of estimated state/action values in reinforcement learning",
abstract = "Under/overestimation of state/action values are harmful for reinforcement learning agents. In this paper, we show that a state/action value estimated using the Bellman equation can be decomposed to a weighted sum of path-wise values that follow log-normal distributions. Since log-normal distributions are skewed, the distribution of estimated state/action values can also be skewed, leading to an imbalanced likelihood of under/overestimation. The degree of such imbalance can vary greatly among actions and policies within a single problem instance, making the agent prone to select actions/policies that have inferior expected return and higher likelihood of overestimation. We present a comprehensive analysis to such skewness, examine its factors and impacts through both theoretical and empirical results, and discuss the possible ways to reduce its undesirable effects. {\textcopyright} 2017 Neural information processing systems foundation. All rights reserved.",
author = "Liangpeng ZHANG and Ke TANG and Xin YAO",
note = "This paper was supported by Ministry of Science and Technology of China (Grant No. 2017YFB1003102), the National Natural Science Foundation of China (Grant Nos. 61672478 and 61329302), the Science and Technology Innovation Committee Foundation of Shenzhen (Grant No. ZDSYS201703031748284), EPSRC (Grant No. J017515/1), and in part by the Royal Society Newton Advanced Fellowship (Reference No. NA150123).; 31st Conference on Neural Information Processing Systems, NIPS 2017 ; Conference date: 04-12-2017 Through 09-12-2017",
year = "2017",
month = dec,
language = "English",
isbn = "9781510860964",
series = "Advances in Neural Information Processing Systems",
publisher = "Neural Information Processing Systems Foundation",
pages = "1805--1815",
editor = "{VON LUXBURG}, Ulrike and {GUYON }, {Isabelle } and {BENGIO }, {Samy } and WALLACH, {Hanna } and FERGUS, {Rob } and VISHWANATHAN, {S.V.N. } and Roman GARNETT",
booktitle = "Advances in Neural Information Processing Systems, 30 : 31st Annual Conference on Neural Information Processing Systems (NIPS 2017)",
}