The community detection problem involves making inferences about node labels in a graph, based on observing the graph edges. This paper studies the effect of additional, non-graphical side information on the phase transition of exact recovery in the binary stochastic block model (SBM) with n nodes.When side information consists of noisy labels with error probability α, it is shown that phase transition is improved if and only if log( 1−α α ) = Ω(log(n)). When side information consists of revealing a fraction 1 − ǫ of the labels, it is shown that phase transition is improved if and only if log(1/ǫ) = Ω(log(n)).For a more general side information consisting of K features, two scenarios are studied: (1) K is fixed while the likelihood of each feature with respect to corresponding node label evolves with n, and (2) The number of features K varies with n but the likelihood of each feature is fixed. In each case, we find when side information improves the exact recovery phase transition and by how much. In the process of deriving inner bounds, a variation of an efficient algorithm is proposed for community detection with side information that uses a partial recovery algorithm combined with a local improvement procedure. DRAFT Side Information Observed Graph community − −−−− → detection error error True Labels Detected communities Side Information Graph + side information community − −−−− → detection True Labels Enhanced detection Fig. 1. (top) standard community detection (bottom) Community detection with side information Community detection outcomes fall into several broad categories in terms of residual error as the size of the graph n grows, enumerated here in increasing order of strength: Correlated recovery refers to community detection that performs better than random guessing [19]-[23]. Weak recovery means the fraction of misclassified labels in the graph vanishes with probability converging to one [24]-[26]. Exact recovery means correct recovery of all nodes with probability converging to one [18], [27], [28]. This paper concentrates on the exact recovery metric. 1 A few results have recently appeared in the literature on the broader community detection problem in the presence of additional (non-graphical) information. Mossel and Xu [29] studied the behavior of belief propagation detector in the presence of noisy label information. Cai et al. [30] studied the effect of knowing a growing fraction of labels on correlated and weak recovery. Neither of [29], [30] includes a converse, so they do not establish phase transition. Kadavankandy et al. [31] studied the single-community problem with noisy label observations,showing weak recovery in the sparse regime. Kanade et al. [32] showed that partial observation of labels is unhelpful to the correlated recovery phase transition if a vanishing portion of labels 1 Formally, let en denote the number of misclassified nodes. Then, correlated recovery means limn→∞ P( en n < 0.5) = 1. Weak recovery means limn→∞ P( en n < ε) = 1 for any positive ε. Exact recovery means limn→...