One of the most popular contemporary graphical password approaches is the Pattern-Lock authentication mechanism that comes integrated with the Android mobile operating system. In this paper we investigate the impact of password strength meters on the selection of a perceivably secure pattern. We first define a suitable metric to measure pattern strength, taking into account the constraints imposed by the Pattern-Lock mechanism's design. We then implement an app via which we conduct a survey for Android users, retaining demographic information of responders and their perceptions on what constitutes a pattern complex enough to be secure. Subsequently, we display a pattern strength meter to the participant and investigate whether this additional prompt influences the user to change their pattern to a more effective and complex one. We also investigate potential correlations between our findings and results of a previous pilot study in order to detect any significant biases on setting a Pattern-Lock. © 2014 Springer International Publishing.