Star ratings that are given by the users of mobile apps directly impact the revenue of its developers. At the same time, for popular platforms like Android, these apps must run on hundreds of devices increasing the chance for device-specific problems. Device-specific problems could impact the rating assigned to an app, given the varying capabilities of devices (e.g., hardware and software). To fix device-specific problems developers must test their apps on a large number of Android devices, which is costly and inefficient. Therefore, to help developers pick which devices to test their apps on, we propose using the devices that are mentioned in user reviews. We mine the user reviews of 99 free game apps and find that, apps receive user reviews from a large number of devices: between 38 to 132 unique devices. However, most of the reviews (80%) originate from a small subset of devices (on average, 33%). Furthermore, we find that developers of new game apps with no reviews can use the review data of similar game apps to select the devices that they should focus on first. Finally, among the set of devices that generate the most reviews for an app, we find that some devices tend to generate worse ratings than others. Our findings indicate that focusing on the devices with the most reviews (in particular the ones with negative ratings), developers can effectively prioritize their limited Quality Assurance (QA) efforts, since these devices have the greatest impact on ratings.

In the past few years, the number of smartphone apps has grown at a tremendous rate. To compete in this market, both independent developers and large companies seek to improve the ratings of their apps. Therefore, understanding the user's perspective of mobile apps is extremely important. In this paper, we study the user's perspective of iOS apps by qualitatively analyzing app reviews. In total, we manually tag 6,390 reviews for 20 iOS apps. We find that there are 12 types of user complaints. Functional errors, requests for additional features, and app crashes are examples of the most common complaints. In addition, we find that almost 11% of the studied complaints were reported after a recent update. This highlights the importance of regression testing before updating apps. This study contributes a listing of the most frequent complaints about iOS apps to aid developers and researchers in better understanding the user's perspective of apps.