Globally, ODL institutions experience mismatch between scalability of numbers and scalability of success rates. This study explored the scalability of success rates in open, distance e-learning as perceived by the learners within the "Chain of Response Model." The primary aim of the study was to look at online learners' success rate by focusing on two institutional factors drawn from the Model, namely: the learner's study modules related challenges and support services. The results of an online survey of 180 undergraduate and postgraduate online learners of Egerton University, Kenya, showed: (a) the response rate of 16%; (b) a mixture of hardware, software and personal factors were identified as pre-requisites for e-learning success: (c) a number of mathematically-based modules were identified as risks to success in online studies; and (d) while the learners saw the learner support services as important they were less satisfied with their provision. The present study points to two broad areas that require further studies. First, qualitative look into specific challenges that learners face with respect to learner support service provisions, modules interactivity, and those identified as difficult to follow and thus posing risks to the learners' success. Second, investigation into tutor-learner contacts with the view of identifying whether such contacts are reactive or proactive.