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Digital Prototypes: better user feedback, better products


... User-centered design is not only about people, but it's also about iterating, going back to the users [...] not only [...] asking questions but showing things to people to get more accurate feedback.

Jakob Kisker


The most successful digital products and services not only have a deep understanding of their user, but also engage the end-users in an iterative process of continual improvement, by collecting and applying their feedback. The key question is how good or accurate is the feedback? The more accurate the feedback, the better the improvements will be during the next iteration, and ultimately, the more likely that the end product will be used.

The process

Many quick prototypes rely heavily on pen/paper, require narration to set the stage for the user, and ask for a good amount of thinking on the part of the user. The more the user is imagining, the less accurate and consistent the feedback will be from person to person. Jakob estimates that paper prototypes give feedback that is about 50% accurate, digital prototypes about 70%, Minimum Viable Product (MVP) of the actual product at 90%, with the final product being 100%. Digital prototypes are quick, cheap, and much more accurate to test. They ask less imagination of the user so the feedback will be less subjective and more aligned with what might happen when they are interacting with a real, finished product.

Digital prototyping follows the same iterative steps that traditional rapid prototyping does, but takes the idea of “real enough to feel” to the next level. It elevates paper sketches into designed screens that users can interact with, absent the narration required to take them through a paper prototype. There are a number of digital prototyping platforms that have emerged in the last several years, almost all of which offer a free version and will allow users to input feedback directly into the platform.

Added benefit - attract funding

Besides the fact that better feedback during product development leads to more effective solutions, digital prototyping can actually help attract more funding. Funders like to know their investment is secure and will provide a good return. More accurate feedback during product/service development makes that more likely.


Spotlight: Jakob Kisker & WSUP


Jakob Kisker is a Design Researcher for Water & Sanitation for the Urban Poor (WSUP), working in their Innovation and Consumer Needs team in London. His work focuses on creating more relevant and more future proof products and services. WSUP’s latest project, PULA, in partnership with UX and BoP inc, is focused on fecal sludge management (FSM) in sub-Saharan Africa and is leveraging the power of digital prototyping to amazing effect.

Africa is on the verge of being flooded with affordable smartphones, as people from the west continue to upgrade their smartphones and recycle their old ones. That means HUGE opportunities for app development to leverage the power of mobile data to solve problems more effectively, by continuing to seek deeper understanding of users. WSUP was able to get funding for a multi-week digital prototyping of a mobile app for managing fecal sludge. At the time of writing, the work done in Ghana and Kenya secured the funding needed to take the software to MVP testing in Mozambique and Zambia.

Case Study: Ghana's FSM Vacuum Tanker Trucks*



In urban Ghana, most people have pit latrines or septic systems. These must be emptied every 1-5 years, either manually or mechanically, by vacuum tanker trucks. Tanker trucks are the most efficient and hygienic way to handle fecal sludge. However, the current FSM system has multiple inefficiencies that arise in service delivery.

Private service providers in FSM face challenges like unknown customer locations, ineffective marketing, and inability to manage fleets of vehicles. These challenges prevent providers from maximizing their ability to reach consumers with safe, effective sanitation services. The public sector has struggled both to improve dumping practices and provide low-income communities with affordable services.

For both private and public stakeholders, accurate data is crucial for making informed and effective decisions. However, such data is often unavailable, inaccurate, or difficult to leverage towards effective improvements in service delivery, particularly in low-income areas.

Proposed solution

To generate improved data, WSUP proposed developing a mobile, cloud-based application called PULA to strengthen the management and efficiency of emptying services, while providing aggregated and up-to-date data to local governments. This, in turn, would allow for improved sanitation planning, regulation, and contribute toward universal access to safe FSM services in developing cities. Digital prototyping played a crucial role in testing. WSUP’s team used a digital-prototyping platform called Marvel, which makes the iteration and user feedback loop incredibly easy.


Ideation to 1st Digital Prototype: One Month in Ghana


Interviews & Workshop

The WSUP team went to Ghana and began talking to stakeholders to nail down their pains and desired outcomes. The team discovered that customers tend to only schedule their emptying services once their latrines or septic tanks are already full, which happens most consistently in the rainy season. This creates high and low season for business. Truck drivers want more consistent business. Currently to boost their business and income, truck drivers will do emptying runs off the record (not reported to their bosses). Owners want better supervision of their drivers, so that they understand their revenue.

Features Development & App Mock-Up

WSUP applied their field learnings to a design sprint; they drew cheap paper mockups, employing Crazy 8s for rapid ideation, to think through key features, the layout of the mobile app, and how to link all the screens together. They then used Adobe Illustrator to digitally sketch the paper mock-us and loaded them into Marvel. They tested the Marvel site with stakeholders, to validate the chosen application features.

Feature Refinement & App Improvement: Kenya (2nd Iteration)

Incorporating user feedback from the first iteration in Ghana, the team had another design sprint. They took the improved Marvel site to the same stakeholders in Kenya, where they:

  • Explored needs, wants, and limitations related to the PULA application through interviews and workshops with relevant stakeholders in Kisumu and Nairobi.
  • Gained feedback on the features developed in Ghana.
  • Ranked existing features and developed new features based on qualitative research in Kenya.


Outcome/ Solution


From the two rounds of iteration, in two different markets, the most promising features were:

  • Active Customer Acquisition: This feature provides:
    • Drivers: the ability to reach out to more potential customers, growing their income
    • Owners: increased driver incomes means increasing the company’s revenue
    • Individual customers/the general public: reminders to empty their pits more frequently, reduced rates, more efficient services, and improvements to environmental/public health as frequently emptied latrines do not overflow
  • Truck tracking: This feature provides:
    • Owners: better oversight of their fleet, increased ability to direct drivers to jobs more efficiently, thus creating cost savings
    • Individual customers: more cost-effective services, as a result of a better managed truck fleet, and a reduction in fees
    • Public sector: increased insight into the state of FSM in their city; improved public and environmental health through prevention of vacuum tank operators emptying their tanks outside of designated sewage treatment/disposal sites
  • Performance dashboard: This feature provides:
    • Public sector: insight into how, where and when pit latrines are emptied in their city, further informing investment and analysis; increased ability to attract funding for sanitation improvements.

What’s next: the future of digital prototypes in sanitation


With the impending explosion of smartphones in the developing world, there are huge opportunities for UCD organizations in the WASH sector to use mobile apps and digital prototypes to improve the quality of user feedback they receive during development, iteration, and improvement of their offerings. Applications of digital prototyping could include having increased consumer engagement, improved operational efficiency, collecting detailed and up-to-date field data, targeted marketing opportunities, and perhaps even opportunities for organizations to share and learn from each other.

*For a fully developed case study of this project, check out this publication from WSUP.


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