As the world is getting more digitalized, the development and usage of mobile applications have increased. Mobile digital services have become more efficient than the traditional non-digital, being a prominent part of today's society. Hence, studies on mobile applications' usability have become a focal focus for scholars, resulting in various usability attributes. However, due to pervasive digitalization, research scholars argue that there is a need for more research regarding the development and usability of mobile applications. Through a qualitative case study, the aim was to investigate how usability affects young adults' investment behavior using Avanza's mobile bank applications. Nielsen's theory of good usability consists of five attributes: learnability, effectiveness, memorability, error, and satisfaction. Based on eleven semi-structured interviews, our study reveals that. First, the usability attributes are strongly entangled and interdepended of each other. Second, good learnability creates good memorability, decreasing the number of errors and making the mobile application more effective. Third, two new attributes that complement Nielsens' theory of good usability have been identified, nudging and trust. Fourth and finally, in line with previous research scholars, our study reveals a need for further research on the role of usability in mobile applications in various contexts to enhance our understanding of how the design of a mobile application can affect the behavior of the users.

Workplace safety, particularly in manual handling tasks, is a critical concern that hasbeen increasingly addressed using advanced risk assessment tools. However, pre-senting the complex results of these assessments in an easily digestible format re-mains a challenge. This thesis focused on designing and developing a user-friendlyweb application to visualise risk assessment data effectively. Grounded in a robusttheoretical framework that combines user experience principles, and data visualisa-tion techniques. The study employed an iterative, user-centric design process to de-velop the web application. Multiple visualisation methods, such as pie charts for vis-ualising risk distribution, bar chart, and line chart for time-based analysis, were eval-uated for their effectiveness through usability testing. The application's primary con-tribution lies in its efficient data visualisation techniques, aimed at simplifying com-plex datasets into actionable insights. This work lays the groundwork enabling futuredevelopment by pinpointing areas for improvement like enhanced interactivity andaccessibility. / Belastningsergonomiska risker i arbetsmiljön, särskilt i uppgifter som involverarmanuell hantering, är en kritisk fråga som alltmer har adresserats med hjälp av avan-cerade riskhanteringsverktyg. Men att presentera de komplexa resultaten av dessabedömningar i ett lättillgängligt format kvarstår som en utmaning. Denna avhand-ling fokuserade på att designa och utveckla en användarvänlig webbapplikation föratt effektivt visualisera riskbedömningsdata. Studien bygger på en robust teoretiskram och kombinerar principer för användarupplevelse med datavisualiseringstekni-ker. Webbapplikationen har utvecklats med hjälp av en iterativ och användarcentre-rad designprocess. Flera visualiseringsmetoder, såsom cirkeldiagram för att visuali-sera riskfördelning, stapeldiagram och linjediagram för tidsbaserad analys, utvärde-rades för deras effektivitet genom användningstester och utvärderingsformulär. Ap-plikationens primära bidrag ligger i dess effektiva datavisualiseringstekniker, somsyftar till att förenkla komplex information till handlingsbara insikter. Detta arbetelägger grunden och möjliggör framtida utveckling genom att peka ut områden förförbättring, som förbättrad interaktivitet och tillgänglighet.