Abstract: Software code review is a well-established software quality practice. Recently, Modern Code Review (MCR) has been widely adopted in both open source and proprietary projects. Our prior work shows that review participation plays an important role in MCR practices, since the amount of review participation shares a relationship with software quality. However, little is known about which factors influence review participation in the MCR process. Hence, in this study, we set out to investigate the characteristics of patches that: (1) do not attract reviewers, (2) are not discussed, and (3) receive slow initial feedback. Through a case study of 196,712 reviews spread across the Android, Qt, and OpenStack open source projects, we find that the amount of review participation in the past is a significant indicator of patches that will suffer from poor review participation. Moreover, we find that the description length of a patch shares a relationship with the likelihood of receiving poor reviewer participation or discussion, while the purpose of introducing new features can increase the likelihood of receiving slow initial feedback. Our findings suggest that the patches with these characteristics should be given more attention in order to increase review participation, which will likely lead to a more responsive review process. This paper is an extended abstract of a paper published in the Empirical Software Engineering Journal. The full article can be found at: http://dx.doi.org/10.1007/s10664-016-9452-6