Design Thinking - Module 4 - Prototyping and Testing Strategies - Dr. Rohan Dasgupta

Prototyping
and Testing
Strategies
Module No. 4
Dr. Rohan Dasgupta

4.1. Concept of Prototyping &
its purpose in Design Thinking

Concept of Prototyping
● A prototype is an early sample or model of a product or service.
● It makes abstract ideas tangible and testable.
● Prototypes allow quick communication of design intent.
● They help identify usability issues before large investments.
● Serve as a low-risk way to test assumptions.
● Core principle: “Prototyping is a tool for thinking and learning.”

Purpose of Prototyping in Design Thinking
● Encourages experimentation and iteration.
● Helps align team members and stakeholders on shared vision.
● Bridges the gap between concept and reality.
● Provides opportunities for user engagement and feedback.
● Accelerates innovation by reducing uncertainty.
● Supports the mindset: “Fail early, fail cheap, sail forward.”

Low-Fidelity (LoFi) Prototypes
● Simple, quick, and inexpensive to create.
● Examples: paper sketches, cardboard models, LEGO builds.
● Focus on broad concepts rather than fine details.
● Useful in early design stages for brainstorming.
● Encourages creativity and exploration.
● Helps gather quick feedback without heavy investment.

High-Fidelity (HiFi) Prototypes
● More detailed and closer to the final product.
● Examples: digital mockups, interactive apps, 3D printed models.
● Provides realistic user interactions and experiences.
● Useful for usability testing and refining design details.
● Requires more time, skill, and resources to build.
● Helps stakeholders visualize the final look and feel.

Minimum Viable Product (MVP)
● Simplest working version of the product.
● Includes only the most essential features.
● Allows real-world testing with target users.
● Helps validate core assumptions quickly.
● Reduces risk of over-investing in unproven ideas.
● Often used in startups to test market potential.

Examples of Different Types of Prototypes
● LoFi Prototype
○ Product: Paper sketches of a new mobile app interface (drawn screens with arrows
showing navigation).
○ Service: Role-play with students acting out steps of a new library self-checkout
process using cue cards.
● HiFi Prototype
○ Product: Interactive digital prototype of a smart home control app built in Figma.
○ Service: Detailed storyboard of a hospital patient check-in experience with
realistic visuals and dialogue.
● MVP Prototype
○ Product: A basic version of an online food delivery app that allows only browsing a
limited menu and placing orders (no payment gateway yet).
○ Service: A pilot program for bike-sharing in a small neighborhood with just a few
stations and limited bikes to test demand.

4.3. Prototyping strategies for
products and services

Prototyping strategies for Products
● Paper Sketches: Quick hand-drawn layouts to explore concepts cheaply.
Image
Courtesy:
Medium

● Cardboard/Physical Models: Rough shapes for testing ergonomics and form.
Image
Courtesy:
WebJunction

Image
Courtesy:
All3DP
● 3D Printed Models: Accurate representations to check size, fit, and usability

● Digital Wireframes: Layout of apps/websites created using Figma/Sketch.
Image
Courtesy:
Figma

● Interactive Mockups: Clickable app/site versions simulating navigation.
Image
Courtesy:
Inkscape

● Wizard of Oz Technique: Product appears automated, but humans simulate functions in
the background.
Image
Courtesy:
Nielsen
Norman
Group

Summary: Prototyping strategies for Products
● Paper Sketches: Quick hand-drawn layouts to explore concepts cheaply.
● Cardboard/Physical Models: Rough shapes for testing ergonomics and form.
● 3D Printed Models: Accurate representations to check size, fit, and usability.
● Digital Wireframes: Layout of apps/websites created using Figma/Sketch.
● Interactive Mockups: Clickable app/site versions simulating navigation.
● Wizard of Oz Technique: Product appears automated, but humans simulate functions in
the background.

Activity: Prototype Challenge #1
● Group formation: 3-4 members in a group
● Choose any one solution:
○ Self service canteen
○ Online assignment submission portal
○ Event registration process
● Prototype: For the chosen solution, propose one of each
○ Lo-fi prototype
○ Hi-fi prototype
○ MVP concept

Prototyping strategies for Services
1. Role-Playing
● In this method, team members act out the roles of customers and service providers.
● Helps simulate interactions and identify emotional responses.
● Example: Students act as “patients” and “doctors” to test a new hospital check-in
process.
● Benefits: Uncovers hidden challenges in body language, timing, and communication.

2. Storyboarding
● Visual representation of the sequence
of events in a service experience.
● Each frame highlights a customer
touchpoint or decision.
● Example: A storyboard showing a
student ordering food in the canteen
app and picking it up.
● Benefits: Easy to spot pain points and
gaps in the journey.

3. Service Blueprinting
● A detailed diagram of the service process, showing:
● Frontstage (visible): What the customer sees.
● Backstage (invisible): Internal processes and staff actions.
● Example: Online food delivery app → Customer orders, backend kitchen prepares, delivery
person assigned.
● Benefits: Clarifies dependencies between staff, technology, and customers.

4. Experience Prototyping
● Recreates the real environment in which the service occurs.
● Example: Setting up a mock bank counter or help desk in the classroom to test interactions.
● Benefits: Users feel the actual flow, waiting time, and atmosphere.

5. Customer Journey Mapping
● Plots the emotions, thoughts, and actions of the customer at each stage of the service.
● Example: Mapping how students feel while registering for an exam online → confusion,
satisfaction, frustration.
● Benefits: Focuses on emotional highs and lows to improve user experience.

6. Pilot Programs
● A small-scale trial version of the service before a full rollout.
● Example: Launching a limited bus shuttle service on campus to test routes and demand.
● Benefits: Provides real-world data, reduces risk, and allows quick iteration.

Summary: Prototyping strategies for Services
● Role-Playing: Students/staff act as customers and providers to simulate service flow.
● Storyboarding: Visual sequence of customer journey, highlighting pain points.
● Service Blueprints: Diagrams of frontstage (customer-facing) and backstage (support)
activities.
● Experience Prototypes: Mock setups (e.g., classroom, waiting room) to test service
interactions.
● Journey Mapping: Charting emotions, actions, and touchpoints across service stages.
● Pilot Programs: Limited trial run of the service to test before full-scale rollout.

Activity: Prototype Challenge #2
● Group formation: 3-4 members in a group
● Choose any one service:
○ Self service canteen
○ Assignment submission (offline)
○ Event registration process (offline)
○ Any other service of your choice
● Prototype Strategy:
○ For the chosen service, propose one of prototype strategy and plan accordingly.

Testing Concepts
1. A/B Testing
2. Feedback Loops
3. Usability Testing

Testing Concepts: A/B Testing
● A/B testing (or split testing) is an experiment comparing two versions of a product, service, or
feature to determine which performs better.
● Version A = Control (original design)
● Version B = Variant (new design or change)
● Goal: Test user response objectively using data and evidence.
● It’s like a scientific experiment applied to design decisions.

Why use A/B Testing in Design Thinking?
● Helps validate design assumptions with real users.
● Reduces guesswork in prototype improvement.
● Encourages evidence-based iteration.
● Reveals user preferences and pain points.
● Supports continuous improvement after prototyping.
● In the “Testing” phase, A/B tests guide which version to scale up.

How A/B Testing Works…
● Identify the goal (e.g., increase sign-ups, clicks, satisfaction).
● Create two versions (A and B).
● Randomly split users into two groups.
● Measure performance metrics (quantitative data).
● Analyze results statistically.
● Adopt the better version or iterate further.
● Tip: Keep one variable different between A and B for clarity.

Example: Product
● Scenario: A startup tests two versions of its app’s “Sign Up” button.
● Version A: Blue button, “Register Now”
● Version B: Green button, “Join Us Free”
● Result: Version B increases clicks by 15%.
● Insight: Wording and color both affect user behavior.

Example: Service
● Scenario: A college cafeteria tests two queue systems.
● Version A: One common line
● Version B: Two separate lines for hot & cold food
● Result: Students spend 30% less time waiting in Version B.
● Insight: Service design changes can improve user experience measurably.

Advantages
● Simple and low-cost to implement
● Provides data-driven insights
● Reduces design risk
● Helps optimize prototypes before full-scale launch
● Promotes user-centered decision-making

Disadvantages
● Tests only small design changes effectively
● Requires enough users/data to be valid
● External factors (timing, context) can skew results
● Doesn’t explain why users prefer something — just what works better
TIP: Use A/B testing along with qualitative feedback (like interviews).

Testing Concepts: Feedback Loops
● A feedback loop is a process where the results of an action are fed back into the system to
influence future actions.
● In design, it means learning from user responses and refining the design continuously.
● Core idea: “Build → Test → Learn → Improve.”
● Design evolves through repeated cycles of feedback.

● Ensures user-centered design decisions.
● Reduces errors and wrong assumptions early.
● Encourages continuous improvement.
● Builds a learning mindset among designers.
● Bridges the gap between prototype and final solution.
● Without feedback, design becomes guesswork.

● Types of Feedback Loops
● Positive Feedback Loop
○ Reinforces or ampliﬁes change.
○ Example: A feature users love → designers enhance it further
● Negative Feedback Loop
○ Reduces or corrects undesired behavior.
○ Example: Users ﬁnd navigation confusing → designers simplify it.
Both loops are valuable for guiding iteration.

● Feedback Loop Cycle
● Action: Implement a design or feature.
● Observe: Gather user response or data.
● Reﬂect: Analyze what worked or didn’t.
● Adjust: Modify the design accordingly.
Repeat until user needs and design goals align.

● Example: Product Design
Scenario: A mobile app prototype for food delivery.
Version 1: Long checkout process → users drop off.
Feedback: “Too many steps.”
Revision: Combine address and payment screens.
Result: 30% higher completion rate.
Feedback loop led to a simpler, more effective design.

● Example: Service Design
Scenario: A hospital introduces a new appointment system.
Feedback from patients: “Too confusing; unclear timings.”
Designers observe and simplify booking ﬂow.
Feedback again: “Now it’s easier to use.”
Iterative improvements based on real-world experience.

● Sources of Feedback
● User interviews and surveys
● Observation of user behavior
● Usability testing sessions
● Analytics (clicks, time, errors)
● Peer and expert reviews
● Customer support queries
Collect both quantitative and qualitative feedback.

● Best Practices for Managing Feedback
● Encourage open and honest feedback.
● Separate idea from ego – don’t take feedback personally.
● Document all feedback for future iterations.
● Use visual boards or tools (Miro, Trello) to track loops.
● Involve diverse users for well-rounded insights.

Testing Concepts: Usability Testing
● A method of evaluating a prototype or product by observing real users as they complete tasks.
● Focuses on how easy and effective the design is to use.
● Goal: Identify problems in user interaction and improve user experience.
● It’s not about what users say, but what they actually do.

● Ensures the design is intuitive and user-friendly.
● Reveals hidden usability issues early.
● Saves time and cost by fixing problems before full development.
● Validates whether the design meets user expectations.
● Builds empathy and understanding of user behavior.
● A design that isn’t usable fails, no matter how creative it is.

● Key Questions in Usability Testing
○ Can users understand how to use the design?
○ Can they complete tasks efficiently?
○ Do they make errors? If so, where and why?
○ How satisfied are users with the experience?
○ What improvements can be made?

● The Usability Testing Process
○ Define goals – What do you want to learn?
○ Select participants – Real or representative users.
○ Create test scenarios – Realistic tasks for users to perform.
○ Conduct the test – Observe silently, take notes.
○ Collect feedback – Through observation & interviews.
○ Analyze and improve – Identify pain points & redesign.

● Example : Product Design
○ Scenario: Prototype of a college bus tracking app.
○ Users struggle to find the “Bus Location” button.
○ Feedback: “Icon looks like a map marker, not a bus.”
○ Redesign: Replace icon + add label “Track My Bus.”
○ Result: 80% reduction in user confusion.
○ Small usability tweaks can make a big difference.

● Example : Service Design
○ Scenario: University library self-checkout kiosk.
○ Students forget to scan their ID first → error message.
○ Feedback: “No instruction shown at the start.”
○ Solution: Add visual cue & voice prompt → smoother process.
○ Testing real interactions improves service flow.

● Methods of Usability Testing
Method Description When To Use
Moderated testing Facilitator guides user & asks questions Early prototypes
Unmoderated testing User interacts independently Later stages
Remote testing Conducted online Geographically distant users
A/B testing Compare two design versions During iteration

● Matrices in Usability Testing
📊 Quantitative metrics:
● Task completion rate
● Time on task
● Error rate
● Number of clicks
💬 Qualitative metrics:
● User satisfaction (rating scale)
● Verbal feedback (“think aloud” method)
● Emotional response
🎯 Combine both for a holistic picture.

● Tips for Effective Usability Testing
● Test early and often (even with paper prototypes)
● Observe silently — don’t help users during the test
● Ask open-ended questions afterward
● Record sessions (with consent) for review
● Test with at least 5 users to find most issues
Five users can uncover 80% of usability problems.

4.5. Role of Experimentation & Failure

Role of Experimentation
● Experimentation is at the heart of innovation; it’s about trying ideas quickly and learning fast.
● Encourages exploration, creativity, and curiosity.
● Helps test assumptions and hypotheses through prototypes.
● Transforms abstract ideas into tangible experiences for users.
● Supports evidence-based design decisions — not guesswork.
● Cycle: Build → Observe → Learn → Refine → Repeat
● Experimentation helps designers move from imagination to insight.

Role of Failure
● In Design Thinking, failure = feedback, not defeat.
● Each failed prototype reveals what doesn’t work and why.
● Encourages a growth mindset — learning from mistakes.
● Reduces risk by failing early and cheaply instead of later and expensively.
● Builds resilience and confidence in iterative improvement.
● Motto: “Fail fast, fail forward, learn faster.”
● Every failure brings you one step closer to the right solution.

4.6. Metrics: Desirability, viability &
feasibility

Metrices
● Design Thinking combines creativity with practicality.
● Every idea must be evaluated through three lenses:
○ Desirability → Human / User needs
○ Viability → Business / Sustainability
○ Feasibility → Technical / Operational capability
● Goal: Find the sweet spot where all three intersect →
Innovative, Realistic, and Valuable Solution

Metrices: Desirability (the human lens)
● Focus: What do people want?
● Centers on user emotions, needs, and motivations.
● Asks: “Will people use or care about this?”
● Derived from empathy research, user interviews, and observations.
● Indicators of high desirability:
○ Positive user feedback
○ Ease of use and intuitive design
○ Solves a meaningful problem
● Example: A public transport app that reduces waiting anxiety by showing real-time bus location.

Metrices: Viability (the business lens)
● Focus: Does it make sense to build it?
● Evaluates economic and strategic feasibility.
● Asks: “Can this idea sustain itself financially?”
● Involves:
○ Cost-benefit analysis
○ Market potential
○ Business model fit
○ Long-term sustainability
● Example: A solar-powered streetlight that reduces energy costs and pays back investment in 2
years.

Metrices: Feasibility (the technical lens)
● Focus: Can we actually make it work?
● Checks technical practicality and resource availability.
● Asks: “Do we have the technology, time, and expertise?”
● Involves:
○ Material availability
○ Technological readiness
○ Time and cost constraints
○ Team skills
● Example: Using locally available materials to build a low-cost water filter prototype.

CREDITS: This presentation template was created by Slidesgo, and
includes icons by Flaticon, and infographics & images by Freepik
Thanks!
Do you have any questions?
rohan.dasgupta@aiktc.ac.in
9967569336
https://www.linkedin.com/in/drrohandasgupta/

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