ORIGINAL ARTICLE Personal information retrieval: smartphones vs. computers, emails vs. files Ofer Bergman 1 & Nimrod Yanai 1 Received: 5 January 2017 /Accepted: 20 November 2017 # Springer-Verlag London Ltd., part of Springer Nature 2017 Abstract Millions of people retrieve their emails and files using their smartphones, yet smartphone retrieval of such personal information has never been studied or compared to retrievals from PCs. In our within-subjects study, we compared the retrievals of our 57 participants in four conditions: files using PCs, emails using PCs, files using smartphones, and emails using smartphones. Our results indicate that when using smartphones, retrievals were significantly less successful and efficient than when using PCs, casting doubt on the implicit assumption that the use of these devices is equivalent. Our results also indicate that participants used the search facility for emails about seven times more than for files, which can encourage vendors to invest more efforts in improving email search engines and file navigation systems. Finally, we found that the tendency to search shows interpersonal differences but consistency across different situations for the same individual and therefore can be regarded as a personal trait. Future research can attempt to explain the search tendency trait in terms of cognitive abilities and personality traits, incorporating it to well-established theories. This may pave the way to a new trait-related theory in the field of information science. Keywords Personal information management . Smartphones . Information retrieval . Files . Emails 1 Introduction Current smartphones allow users to carry out actions they traditionally undertook using their PCs—including accessing their personal information, such as their emails and files. Millions of users retrieve their emails and files using their smartphones on a daily basis. However, smartphone retrieval of personal information has never been measured in a quanti- tative study or compared to PC retrieval. In this study, we compared file and email retrievals using smartphones and PCs. We recorded our 57 participants re- trieving their files and emails one at the time, upon our re- quest. Both files and emails were cloud-based, and we assigned them to be retrieved using a PC or smartphone at random. This procedure allowed us to compare personal smartphone vs. PC use and email vs. file retrievals, as well as an interaction effect—thereby testing for retrieval type, success, and efficiency. The aims and motivations for this study were threefold: (a) Comparing the use of smartphones to PCs when engag- ing in exactly the same tasks. The smartphones’ display and input interface is substantially smaller than that of PCs [1]; therefore, we hypothesized that the use of smartphones will result in reduced performance com- pared to the use of PCs. Positive results can cast doubt on the implicit assumptions that performance for both devices is equivalent, thereby commencing a sequence of future studies that test the effect of display and input interface size on performances for various other tasks and increase awareness that could help users make an in- formed choice between devices per use. (b) Comparing email to file retrieval. Both emails and files are personal information that people manage for their own retrieval [2]. However, it is not clear in which way these collections resemble and in which way they differ from one another. We hypothesize that because emails have a well-defined and easy to remember attribute, which is the sender’ s name, participants will search for emails much more than they would for files, which lack such an attribute. Identifying users’ retrieval preferences * Ofer Bergman bergmao@mail.biu.ac.il 1 Department of Information Science, Bar-Ilan University, 52900 Ramat-Gan, Israel Personal and Ubiquitous Computing https://doi.org/10.1007/s00779-017-1101-6