## 2 Materials and Methods
### Questionnaire Validation  
At the beginning of the study, we held three meetings with stakeholders from two institutions related to environmental issues: the General Environmental Administration of the CARM, and _Reinicia_, a non-profit organization specializing in the life-cycle management of electrical and electronic devices for compliance with environment regulations. The roles of the interviewees were general manager, environment technician, and institutional relations representative. Understanding their viewpoint helped us to structure and articulate the survey better, as well as to avoid possible gaps and misconceptions.  
Once an initial version of the survey had been prepared, it was piloted among 20 software development practitioners, in an endeavor to gather external feedback that would improve the questionnaire before its delivery. The experts were provided with a validation questionnaire, divided into four parts: (1) presentation letter (i.e., clarity, suitability, length, and quality of the presentation letter sent to the potential participants in the survey); (2) questionnaire instructions (i.e., clarity, suitability, quantity, and quality); (3) questionnaire items (i.e., logical order of the questions, clarity of the writing, suitability of the answer options, number of questions, adaptation to the recipients, and efficiency in providing the data required); and (4) a general evaluation of the survey (i.e., validity of the survey content). Appraisers rated items on a 4-point Likert scale from 1 (bad) to 4 (excellent). In addition, there were five open questions to make it easy to propose the changes related to each part of the questionnaire, and to make any other remarks.  
The feedback obtained was generally positive, and it was only necessary to make small changes. Some recommendations related to the format of the survey, and not to the content itself. Throughout the survey, there were also comments asking for more direct statements and questions, or for clearer explanations.  
\begin{table}
\begin{tabular}{c l l} \hline \hline \#Q & \multicolumn{1}{c}{**Practices**} & \multicolumn{1}{c}{**Source**} \\ \hline
1 & Requirements reuse & \\
2 & Code reuse & \\
3 & General sustainability policies (how the company operates) & \\
4 & Specific sustainability requirements & \\
5 & Principles or requirements for usability and user experience in the development & \\  & of products & \\
6 & Principles or requirements for accessibility in the development of products & \\
7 & Principles or requirements of internationalization in the development of products & \\
8 & Agile and lean methodologies & \\
9 & Software product lines & \\
10 & Testing and continuous integration & \\
11 & Standardization of practices, tools, technical solutions, etc. & \\
12 & Certification in some sustainability standard (for example, ISO 14001 and/or EMAS) & \\
13 & Consideration of sustainability when software systems and services are purchased & \\  & or outsourced & \\
14 & Cloud computing and virtualization services & \\
15 & Use of “green” data center infrastructures (using renewable energies) & \\
16 & Big data and data mining & \\
17 & Internet of things & \\
18 & Virtual reality and augmented reality & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Technical practices analyzed in this study.