The main query of this paper is whether a short mindfulness intervention has an impact on the effectiveness and culture in stand-up meetings of agile development teams. In the following subsections we will discuss (1) the perceptions of the teams with respect to our research question, (2) the embedding of the exercise in a broader organizational setting and barriers to its adoption, and (3) directions for future research.
5.1 Three Minute Breathing Exercise in Agile Teams, Does It Work?
The trial shows that even short mindfulness exercises, such as the here presented three minute exercise have a positive impact on the teams similarly to those reported in other domains (compare Table 4). The data indicates a self-reported improvement along five of the ten questionnaire items, particularly: (1) participants listened well to each other, (2) Everyone is involved in the decision-making process, (3) the meeting was effective, (4) the interaction in the meeting was good, and (5) the emotional responses within the meeting were healthy. The questions with the biggest difference to the baseline were Q01 Everyone is involved in the decision-making process, and Q05 participants listened well to each other. These perceptions were supported by the qualitative data (n = 14), e.g.: “The 3 min of silence helped me rest and relax. It helped gather my senses back after a few hours of (usually) stressful work.” (Participant Team 4). We did not observe any statistically significant negative effects in our data. In the placebo group the question Q02 had a statistically not significant decrease compared to the baseline measurement. Here we could raise the question if the Stravinky song had a distracting effect on the team and its vision during the meeting. Looking back at our research question we will now lead the discussion in two ways: (1) how the exercise can support building emotional intelligence and leadership skills in the individual, and (2) how the exercise can help building mindful teams.
Taking the perspective of the individual our findings indicate that the breathing exercise could help agile team members and team leaders to build up their emotional leadership skills. As pointed out by Porthouse and Dulewicz  emotional leadership competencies (e.g., emotional resilience, sensitivity, self-awareness, conscientiousness) are of greater importance for leaders in agile projects compared to traditional projects. As the leadership skills and style of individual managers have a big impact on the culture of an organization, emotional leadership skills are important for the success of agile methods. A meta-analysis conducted by Giluk  on the relationship between mindfulness and the Big Five personality traits shows relationships with neuroticism, negative affect, and conscientiousness, but also with agreeableness.
Taking the perspective of the team our findings indicate that the practice could help building agile teams. Self-managing teams are considered to be one of the corner stones of agility, yet they are difficult to establish . The five dimensions of agile teamwork, such as shared leadership, team orientation, redundancy, learning and autonomy [28, 40] require shared decision making and the ability to listen to each other and understand each others opinions, as supported by the breathing exercise. Further, similarly to what McAvoy et al.  call ‘Doing’ Agile vs. ‘Being’ Agile, our experiences with the trial indicate that the exercise could help build up mindful behaviour, which helps the team understand agility and agile practices in context rather than blindly following them. The lack of focus can be an issue for agile and entrepreneurial teams . Hafenbrack et al.  researched the positive influence of mindfulness on decision making and the sunk-cost bias, the tendency to continue investing in a project once time, money or effort was invested, although that project might not be a viable initiative after all. Stettina and Smit  researched agile teams working in entrepreneurial settings. The results reveal that when trying to handle many project requests due to customer pressure, mindfulness could help making better decisions on what projects to follow.
5.2 Mindfulness in Our Case Organisations: Barriers to Adoption
Our quantitative results show that mindfulness enhances qualities of effectiveness and team cooperation in the daily working culture of an agile team. The qualitative open questionnaires distributed to the teams after the trial, however, draw another perspective on our findings. While several participants saw the personal use of the exercise, none would continue it in a public setting. As a participant from Team 2 commented: “For some members, the pause before the standup was useful, because they could focus on their activities done in the previous day. But for the rest of the team, the exercise was considered just not suitable with their own way of working.” Several participants in Team 4, for example, indicated that the fact that they conducted the exercises in an open space, they felt looked at by other teams. Others indicated, they would continue with the breathing exercise on their own rather than in the team setting: “Yes, I want to do those exercises more often. I have chosen to do this at home and not at work.” (Participant Team 7). So, although the results show statistically significant increases of effectiveness on several entries, the perceived usefulness does not raise to the level that the participants want to keep on using it in a public setting. The teams apparently encountered a barrier to introduction of these practices.
This raises the more general question of what conditions could support the adoption of these type of mental practices in agile teams. From the literature (cf. ) we know a few: support of management for these practices, voluntary participation and a safe team climate. Management support for these practices seems obvious: if leaders do not support these practices it will not happen. In that respect these mental practices do not differ from other agile team practices that help teams perform better. As a line of research, this would be interesting to look into.
Voluntary participation is a necessary corollary of these type of practices. It enhances intrinsic motivation, which is an important mediator of success of team practices (cf. [41, 42]). Lastly, also a safe team climate is important. If, as the qualitative data examples showed, people feel exposed, the practices will not function very well. That is a general factor for well-functioning teams: psychological safety is a crucial characteristic of successful teams. If such a climate is absent, social defense mechanisms will come into play and diminish team performance. Safety has both an environmental side (what space is the team working of meeting in, open or closed) and a communicative side: do people feel safe to utter difficulties, ask questions, disagree, praise each other, etc. In general it means that within the team culture or the organization, it is recognized that emotions play a role and are not subdued. It is generally known from psychological research into emotional agility that if this happens, they will play out in a different but uncontrolled way with mostly negative effects on team climate and effectiveness.
5.3 Mindfulness in Agile Project Teams: A Preliminary Research Agenda
Having studied the results of a mindfulness intervention in agile teams and discussed its relation to existing literature, we now continue to discuss a potential future research agenda. The following is a thematic list of questions, not aiming to be exhaustive, but as possible entry points for an exploration of mindfulness in agile teams:
Effects on leadership competencies and team development. From Porthouse and Dulewicz  we know that emotional leadership competencies are more important in agile project teams compared to traditional project teams. Also shared leadership is an integral aspect of agile teams and can be difficult to acquire . How does mindfulness influence the development of leadership competencies and emotional intelligence? What role do mindfulness practices play in team development?
Effects on decisions. From Hafenbrack et al.  we know that meditation practices are reducing sunk-cost bias. What types of decisions do mindfulness practices have an impact on?
Lengths of training and lengths of effect. In this trial we worked with a brief mindfulness exercise at the beginning of a short agile meeting. We did not, however, measure the impact of this short exercise on a longer type of meeting. It could be that the enhancing effect wears off quickly and that for longer meetings the exercise needs to be repeated several times in order to gain its lasting effect. Also, in clinical research, experiments have been more intense in nature. It would be interesting to see if a whole team that volunteers to submit to a whole intensive program will see even better results. Do longer, more intense mindfulness exercises have greater impact on agile teams? Do short mindfulness exercises also have an impact on longer agile meetings? Do short mindfulness practices become increasingly more effective over time?
Implementation. Although teams indicated that they benefited from the mindfulness exercise they also communicated that they did not want to continue the exercise once the experiment ended. This is an interesting observation which has a contradicting tension. It would be interesting to find out why we were confronted with this tension. What is the best possible organizational culture in which mindfulness will thrive? What is the correlation between the effectiveness of a mindfulness exercise and the maturity of a team?
If the teams are to sustain such a practice on their own, how would they teach to new team members? And if they have to teach the practice to new members, will it be as good as they have learned is form a mindfulness teacher?
Interaction with other practices and routines. In this paper, we have only focused on stand-up meetings during this experiment. Future research can broaden the scope and could determine if there is a correlation between the trait mindfulness and the effectiveness of other types of Agile meetings like retrospectives, sprint planning, sprint review or refinements. It would be interesting to find the effect of other types of mindfulness exercises on the effectiveness of team meetings in Agile teams. What is the effect of other expressions of mindfulness exercises on the effectiveness of meetings in agile project organisations? What is the effect of a mindfulness exercise on other type of meetings in an Agile project organisation?
Types of teams and domains of practice. Our research has focused on software development teams, it would be interesting to expand our understanding towards other domains of practice. We have seen that the trait mindfulness helps make better decisions and is an enabler for the handling of stress. Some types of teams might benefit even more from exercises in the mindfulness spectrum. Teams that are dealing with higher stress levels than software teams or teams that have an acute need for clear and effective decisions would potentially be better candidates in this regards. Portfolio management teams, innovation teams or board room teams would be suitable candidates to consider. What type of teams benefits most from the trait mindfulness?
Costs vs. Benefits. Understanding the costs of a potential implementation is important for management. Hales et al.  discuss the costs of implementing mindfulness in a health care context. What are the costs of implementing mindfulness in project organizations compared to their benefits?
5.4 Threats to Validity
A controlled trial executed within eight teams in three organizations can be more of a challenge to set up in the operational phase than when designed on paper. To avoid potential sources of bias, we followed the recommendations of Pannucci et al.  to prevent bias in clinical trials across stages of research in the planning, data collection, analysis, and publication.
In the pre-trail phase study design and in recruitment selecting a favourable population could impact study results. We addressed selection bias by masking the study purpose. During trail execution, the facilitators educated mindfulness trainers, could have consciously or subconsciously influenced the responses of the team members which could result in higher scores for the treatment teams. We used standardized protocols for execution, data collection and carefully instructed the facilitators, reiterating that masking the study purpose is important for its outcomes. Further, participants might be prone to please the experiment leader and give him the answers he needs for his experiment to be successful. Due to masking the purpose, the participants were not aware of the actual study purpose. Another potential source of bias could be the concept of the breathing exercise, which could polarize some of the participant. Potential skepticism could influence the answers of the participants, provoking interest and random answers. We have tried to notice this within the data set but did not find statistically relevant outliers or noise in the data. In the post-trial phase, bias can occur during data analysis and publication. To address external validity, we compared our findings to existing evidence in the fields of clinical psychology  and in professional organizations . To further improve construct validity we applied a mixed methods approach in collecting and data analysis using qualitative and quantitative sources.