  Gender imbalance in computing education is a well-known issue around the
world. The term "leaky pipeline" is often used to describe the lack of
retention of women before they progress to senior roles. Numerous initiatives
have targeted the problem of the leaky pipeline in recent decades. This paper
provides a comprehensive review of initiatives related to techniques used to
boost recruitment and retention of women in undergraduate computing and related
courses in higher education. The primary aim was to identify interventions or
initiatives (which we called "actions") that have shown some effectiveness. A
secondary objective was to structure our findings as a categorisation, in order
to enable future action discussion, comparison and planning. A particular
challenge faced in a significant portion of the work was the lack of
evaluation: i.e. the assessment of the direct relationship between the
initiatives and the outcomes on retention or recruitment. The actions were
categorised into four groups: Policy, Pedagogy, Influence and Support and
Promotion and Engagement. Policy actions need support and potentially
structural change at institution level. Pedagogy actions are initiatives
related to the teaching of computing courses. The Influence and Support
category includes actions associated with ways to influence women to choose
computing and once enrolled to support and encourage them to stay. Finally,
Promotion and Engagement actions are initiatives to promote computing based
courses and involve engagement and outreach activities. We present our
categorisation, identifying the literature related to actions under each
category and subcategory. We discuss the challenges with evaluating the direct
impact of actions and outline how this work leads towards the next phase of our
work - a toolkit of actions to promote retention and recruitment of women in
computing undergraduate courses.
