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Computer science in UK schools is a subject in decline: the ratio of Computing to Maths A-Level students (i.e. ages 16-18) has fallen from 1:2 in 2003 to 1:20 in 2011 and in 2012. In 2011 and again in 2012, the ratio for female students was 1:100, with less than 300 female students taking Computing A-Level in the whole of the UK each year. Similar problems have been observed in the USA and other countries, despite the increased need for computer science skills caused by IT growth in industry and society. In the UK, the Computing At School (CAS) group was formed to try to improve the state of computer science in schools. Using a combination of grassroots teacher activities and policy lobbying at a national level, CAS has been able to rapidly gain traction in the fight for computer science in schools. We examine the reasons for this success, the challenges and dangers that lie ahead, and suggest how the experience of CAS in the UK can benefit other similar organisations, such as the CSTA in the USA.

Computer science in UK schools is undergoing a remarkable transformation. While the changes are not consistent across each of the four devolved nations of the UK (England, Scotland, Wales and Northern Ireland), there are developments in each that are moving the subject to become mandatory for all pupils from age 5 onwards. In this paper, we detail how computer science declined in the UK, and the developments that led to its revitalisation: a mixture of industry and interest group lobbying, with a particular focus on the value of the subject to all school pupils, not just those who would study it at degree level. This rapid growth in the subject is not without issues, however: there remain significant forthcoming challenges with its delivery, especially surrounding the issue of training sufficient numbers of teachers. We describe a national network of teaching excellence which is being set up to combat this problem, and look at the other challenges that lie ahead.

Previous investigations of student errors have typically focused on samples of hundreds of students at individual institutions. This work uses a year's worth of compilation events from over 250,000 students all over the world, taken from the large Blackbox data set. We analyze the frequency, time-to-fix, and spread of errors among users, showing how these factors inter-relate, in addition to their development over the course of the year. These results can inform the design of courses, textbooks and also tools to target the most frequent (or hardest to fix) errors.

Block-based programming systems, such as Scratch or Alice, are the most popular environments for introducing young children to programming. However, mastery of text-based programming continues to be the educational goal for students who continue to program into their teenage years and beyond. Transitioning across the significant gap between the two editing styles presents a difficult challenge in schoollevel teaching of programming. We propose a new style of program manipulation to bridge the gap: frame-based editing. Frame-based editing has the resistance to errors and approachability of block-based programming while retaining the flexibility and more conventional programming semantics of text-based programming languages. In this paper, we analyse the issues involved in the transition from blocks to text and argue that they can be overcome by using framebased editing as an intermediate step. A design and implementation of a frame-based editor is provided.

Educators often form opinions on which programming mistakes novices make most often -for example, in Java: "they always confuse equality with assignment", or "they always call methods with the wrong types". These opinions are generally based solely on personal experience. We report a study to determine if programming educators form a consensus about which Java programming mistakes are the most common. We used the Blackbox data set to check whether the educators' opinions matched data from over 100,000 students -and checked whether this agreement was mediated by educators' experience. We found that educators formed only a weak consensus about which mistakes are most frequent, that their rankings bore only a moderate correspondence to the students in the Blackbox data, and that educators' experience had no effect on this level of agreement. These results raise questions about claims educators make regarding which errors students are most likely to commit.

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Teaching is the process of conveying knowledge and skills to learners. It involves preventing misunderstandings or correcting misconceptions that learners have acquired. Thus, effective teaching relies on solid knowledge of the discipline, but also a good grasp of where learners are likely to trip up or misunderstand. In programming, there is much opportunity for misunderstanding, and the penalties are harsh: failing to produce the correct syntax for a program, for example, can completely prevent any progress in learning how to program. Because programming is inherently computer-based, we have an opportunity to automatically observe programming behaviour -- more closely even than an educator in the room at the time. By observing students’ programming behaviour, and surveying educators, we can ask: do educators have an accurate understanding of the mistakes that students are likely to make? In this study, we combined two years of the Blackbox dataset (with more than 900 thousand users and almost 100 million compilation events) with a survey of 76 educators to investigate which mistakes students make while learning to program Java, and whether the educators could make an accurate estimate of which mistakes were most common. We find that educators’ estimates do not agree with one another or the student data, and discuss the implications of these results.