Background 
REDCOM Sigma is a mobile app designed specifically for government and military users. Some of the sigma feature includes secure voice calls, video calls and messaging.
Goal
To understand users needs, identify usability issues and opportunities for improvement in the Sigma mobile app that is currently under development.
Process
I was as a UX Researcher on a team of 5. I was involved with each stage of the process, which included: ​
- Heuristic evaluation
- Recruiting participants
- Test plan and moderation
- Data analysis
- Next step
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1. Heuristic evaluation
The team conducted an expert review with 15 heuristics that includes Nielsen's Usability Heuristics. The evaluation team first studied the context of use, use cases, and user profile of the product. Then each of the five evaluators inspected the interface individually. After individual evaluation, findings from each evaluator were written on post-it and aggregated in an affinity diagram. The team then summarized heuristic violations in a detailed report.
2. Recruiting participants 
The client wants to target the lowest denomination in their users and make sure that users with the lowest level of education (high school) can use the app easily. Based on that we set the participant profile.
Criteria: 
●  Must be a freshman in college or a senior in high school, or have graduated from high school but never attended college.
●  Must be in ROTC now or have been in ROTC before.
A screening questionnaire was sent out to the people who were interested. We recruited 8 participants in total. 

3. Test plan and moderation
The participants were asked to perform 3 different tasks to gauge the usability of three major functions of the Sigma Android app: Video call, conference call and chat. Each session was an hour long and the participants were asked to think out loud while performing the task. Five team members took turns being the moderator and observer. The moderator sat with the participants performing the task and the rest of the team observed.  The participants were given $25 gift card as compensation for their time.
4. Data analysis
The findings were made by the following
●  Likert scale after each task (QT)
●  No of Clicks. Think aloud comments. (QL)
●  SUS scale for post-session questionnaire (QT)
●  Incorrect paths (QL)
●  Discrete steps (QL)

Below are the findings based on the 8 usability sessions:
●  Video call is not very easy to use.
●  Starting a conference call is easy to complete and
adding some missing features that can make the experience better.
●  Starting a new chat session is easy though contact list but extremely difficult via Active Chat Session.
5. Next step
All the findings including some recommendations were presented to the Sigma mobile team. We also proposed the team to conduct another usability study before the app launch.