This thesis investigates how researchers can take advantage of the rapid adoption of mobile technology that has brought with it transformations in social and cultural practice; the expectations of what computers are, what they can do, and the role of digital objects in everyday life.
In particular this thesis presents and discuses the use of new App Store style software distribution methods to reduce the cost, in terms of researcher time and hardware, of recruiting a large group of participants for a trial ‘in the wild’ while increasing the potential diversity of users is becoming an attractive option for researchers pursuing the ubicomp vision. It examines the procedures for running large scale trials with the deployment of three applications released to a combined user base of over 135,000 in such a way as to keep the qualitative detail necessary to inform design while gain- ing the diversity of users for claims of generalisability. More generally, it discusses the results that can be expected from this ‘mass participation’ approach, and the ethical responsibilities they place upon researchers.
The contributions of this thesis for mobile HCI show that in large-scale trials, relatively rich qualitative data can be collected along with substantial quantitative data, and that a hybrid trial methodology combining a large- scale deployment with a local trial can be a powerful tool in addressing shortcomings of trials that are either solely local or solely global.
This thesis also contributes guidelines for researchers running large-scale user trials that give consideration to the established research norms and practices, in an attempt to strike a new balance between invasiveness and utility
