Context. With the popularity of Agile methods, many studies about Agile software development has been done by researchers. Among the phases in Agile software projects, planning is critical because it provides an overview of the project and a guiding of future work. In addition, success factors are also mandatory to the success of Agile software development. The current literature focus on the success factors during the whole lifecycle rather than planning phase, and they don’t make an in-depth analysis on the factors. In this thesis, we perform an empirical study to deeply study the critical success factors at agile planning phase. Objectives. The main aim of our research is to identify the critical success factors at Agile planning phase and challenges associated with each factor. We list four objectives to support our main aim. First is to investigate the factors that are mandatory to the success of Agile software development at planning phase. Second is to investigate the challenges associated with each factor. Third is to find out the ways to address these challenges. The last is to identify the consequence of not ensuring these factors. Methods. We employed two research methods: systematic mapping and survey. Systematic mapping is used to identify the critical success factors of entire lifecycle in current literature. To find critical success factors at agile planning phase and make in-depth analysis, we conducted a survey based on an online questionnaire. The online questionnaire was consisted of open-ended questions and was sent to respondents who have experience on Agile development. Results. Through systematic mapping, we identified 13 papers and 47 critical success factors for Agile software development. We also made a frequency analysis for these factors and they will be the effective evidence to support the results of survey. Through the survey, we identified 13 critical success factors at agile planning and made an in-depth analysis for these 13 factors. These 13 factors are divided into two categories: people factor (individual-level, team-level) and process factor. Through the contrastive analysis of mapping results and survey results, we found that 7 factors of survey results are same or similar with some factors shown in mapping. The other 6 factors of survey are first shown. Conclusions. The factors proposed in this thesis are proved that they are important to the success of the project at planning phase. Failure to consider these critical success factors may lead to inefficient planning and even result in the failure ofthe whole project. The challenges and corresponding solutions can help organizations well manage these critical success factors. In conclusion, these detailed descriptions of critical success factors can be used as a guideline to help people increase the chance of successfully developing software with high quality and low cost in practice.

The increase in complexity in software development is followed by higher pressure on several factors such as time-to-market. Software development projects are, however, found to often run over time due to many uncertainties throughout the project. Agile methodologies have become popular in managing software development projects due to their flexible, short-term, and iterative approach to working and planning. There is however a dilemma between being agile without fixed plans, and simultaneously having pressure from management and customers to set and meet a deadline, based on long-term plans. The Agile way of working includes self-organized teams that are involved in project management tasks such as planning and estimating. Agile teams create their own variances of different Agile frameworks as well as their own team characteristics, planning methods, and working ways. Important characteristics of Agile teams are, for instance, cross-functionality and adaptation. Agile planning includes activities such as the breakdown of work, effort estimation, prioritization, task assignment, and planning of iterations. These activities are commonly used in software development teams to manage their work and increase the ability to deliver on time.  This study aims to investigate how software development teams plan their work in practice and what Agile planning activities and Agile team characteristics are regarded, by the development teams, to be important for on-time delivery. Furthermore, it is interesting to investigate how the identified activities and characteristics are reflected in the teams’ actual planning. A case study is conducted on two software development teams at Ericsson’s organization Cloud RAN to investigate this matter.  The studied software development teams are found to use variations of Agile methodologies. The thesis identifies a number of Agile planning activities and team characteristics to be regarded, by the teams, as important for on-time delivery. Many of these activities and characteristics are also reflected in how the teams actually plan. However, there are some contrasting opinions regarding the activities and team characteristics. It can therefore not be stated that all the identified Agile activities and team characteristics are reflected in the actual team-level planning. The thesis also includes other findings impacting teams to deliver on time as well as factors affecting team-level planning.