For UI, UX and product designers. No business degree needed.
Know the number.
Make the decision.
Your redesign ships. Then someone asks: did it work? Learn to answer with numbers, using plain explanations, practice questions and models you can play with.
₹1,299. Opens in your browser through your GLE account.
- 90
- concepts
- 114
- exercises
- 6
- interactive Metric X-Rays
One shop, one week
Fictional figuresHow many people reached each step of buying tea online.
- Looked at a product6,000
- Added to cart2,400
- Started checkout1,800
- Paid for an order900
15%
of visitors end up buying
50%
of people who start checkout finish it
Two true numbers that answer two different questions. Which one is your redesign trying to move?
Denominators and windows
Checkout completion
Beginner · about 2 min
What percentage of the shoppers who started checkout completed an order?
From the kit: Tanpura Teas, one 7-day cohort. Fictional figures.
Work out the 50% yourselfBeautiful screens are
only half the conversation.
You can design the screen. Can you explain what it did?
A scene from week one at a product company. Illustrative, not from the kit.
“Your new onboarding is live. More new users finished setup. Up 12%The number being judged.”
What a new designer might say
“Great. Up 12%. Ship more like it.”
What a designer who knows the numbers says
“Up 12% from what, for which users, and do they stay?”
Five questions to ask before anyone celebrates
- 1
Up from what?
Last week, last quarter, or a group that never saw the change.
- 2
Which users?
An average can hide who actually moved.
- 3
Do they stay?
Finishing setup means little if they never come back.
- 4
Did anything get worse?
Check the numbers that must not drop, like sign-ups.
- 5
What counts as “finished”?
Someone chose that step. Does it show real value?
In the kit you will meet these as Baseline, Segment, Retention, Activation and A/B Test.
The idea to remember
Ask what a number is measured against before you celebrate it.
Made for designers,
not MBAs.
If you can design a screen, you can learn the numbers behind it. Pick the one that sounds like you.
The moment
“Your case study ends: and users loved it.”
In the review, someone asks how you would know. Without a number, it is an opinion.
What the kit gives you
Learn which measure fits what your design is trying to do
Practise it on a real exercise: the right KPI for a redesign
Walk into reviews and interviews knowing the words
Start with these concepts
Not the right fit if you want a design course, or a replacement for a business degree. This kit teaches the numbers behind design decisions, and nothing else.
Learn the language before your first product meeting.
Product teams talk in short phrases. Here is what six of them mean, in plain words.
“Conversion is down.”
Fewer of the people who could have done the thing, signed up, paid or clicked, actually did it.
Kit concept: Conversion Rate
“Did it improve activation?”
Did more new users do the early thing that shows the product worked for them, such as sending a first payment?
Kit concept: Activation
“Retention looks weak.”
Of the people who joined in one week, how many are still using it some time later?
Kit concept: Retention
“Churn spiked this month.”
Of the customers you had on day one of the month, how many were gone by the last day?
Kit concept: Churn
“CAC is too high.”
It costs too much, on average, to win each new customer.
Kit concept: CAC
“Let’s A/B test it.”
Show today’s design to one group and your change to another, chosen at random, then compare the numbers.
Kit concept: A/B Test
Don’t just memorize metrics.
Learn to use them.
One loop on every topic: read it in plain words, practise with real numbers, then play with a model.
01
Understand it
90 concepts. Each starts in plain words and shows where designers meet it. Then comes a worked example, and what the number cannot tell you.
Acquisition · Beginner · Every sector
Conversion Rate
Conversion rate is the share of people, or visits, who did the thing you wanted out of those who had the chance. Orders per 100 sessions is a different number from orders per 100 visitors, even for the same store in the same week. Always say which one you mean.
Where designers meet it
Designers are asked to improve conversion on pages and flows. Before designing, pin down which action counts, who is eligible and what time window applies.
Worked example
Kalpa Home tests a redesigned checkout page for one week.
Redesign: 460 ÷ 10,000 sessions = 4.6%
Original: 400 ÷ 10,000 sessions = 4.0%
A lift of 0.6 percentage points.
It cannot establish
Business value. A higher rate can come from deeper discounts, a narrower high-intent audience, or purchases pulled forward from later.
From the kit’s Conversion Rate page. Fictional figures.
Evidence and interpretation · Choose one · Beginner · about 2 min
The right KPI for a redesign
Sutra Travel, a fictional stays marketplace, is redesigning search. The objective written in the plan is “help travellers find a suitable stay faster”. The design lead has to name the KPI the redesign will be judged on.
Which KPI best ties the redesign to its objective?
Correct
It measures both halves of the objective: shortlisting or booking signals a suitable stay, and the ten-minute window captures speed. Stated as a rate with a fixed window, it can be compared before and after the redesign.
Remember: pick the number that would be embarrassing to improve if the objective were not met.
From the kit’s practice set, shown after an answer. Fictional scenario.
02
Practise it
114 exercises. Some ask you to calculate, some to choose what the evidence supports. Every one has a worked solution.
- 53
- calculate
- 50
- choose one
- 11
- select all
03
See it move
Six interactive Metric X-Rays. Change an input, watch the business result move, and read what the estimate cannot prove. Each one is labelled as an illustrative model.
Checkout economics
Move checkout completion and see estimated orders, revenue and contribution.
Customer acquisition cost
See what rising traffic costs do to CAC while funnel conversion stays the same.
Retention and cohorts
Watch total active users rise while each new cohort retains worse.
AOV versus contribution
Raise order value and still lose money once discounts, returns and variable costs are counted.
Try it on this pageLTV and CAC payback
A margin-aware, assumption-explicit look at lifetime value and payback time.
Experimental lift
Separate percentage points from relative lift, and see how much uncertainty a result carries.
The number went up.
Did the business improve?
Imagine a cart redesign that nudges people into bigger baskets with a discount. Drag the inputs and watch what the business keeps.
Average order value (AOV) is what the typical order is worth. A dashboard shows it going up and calls it a win.
Contribution is what is left of an order after discounts, returns and costs. It is the number that tells you if the business improved.
AOV versus contribution
Illustrative modelAfter the change
Held at the kit’s example: product cost 45% of list value, fees ₹100 per order, ₹120 handling per returned order. Before: ₹1,000 basket, no discount, 8% returned, ₹90 fees.
+6.3%
Change in AOV as reported
₹264
Contribution per order after, was ₹406
−₹143
Change in contribution per order
31.8%
Contribution margin after, of kept revenue
After: from list value to contribution, per order
- List value
- Discount
- Refunds
- Product cost
- Fees
- Return handling
- Contribution
Before the change: ₹406 per order.
The kit’s AOV versus contribution X-Ray, rebuilt with the same arithmetic. At its example inputs it gives +6.3%, ₹406 to ₹264 and 31.8%. Illustrative model, fictional figures.
What to notice, at the kit’s example inputs
- 1
AOV as reported moved +6.3% (₹1,000 to ₹1,063). That is the number a dashboard celebrates.
- 2
Discounts and refunds take it back: ₹188 discount and ₹234 refunded per order after, against ₹0 and ₹80 before.
- 3
Contribution per order went from ₹406 to ₹264 (−35.1%). A higher AOV is not a better order unless contribution rises too.
The idea to remember
Before you celebrate a lift in order value, ask what the business keeps per order.
Try it yourself
One question. One calculation. A better way to think.
A real exercise from the kit, about two minutes. No business degree needed: it is one division, as long as you divide by the right number.
Checked by exact arithmetic, the way the kit checks all 114. Answer it, then open the worked solution.
Denominators and windows
Exercise 1 of 10
Checkout completion
Calculate · Beginner · about 2 min · Numbers set 1 of 2 · Fictional figures
Tanpura Teas, an online tea shop, reviews one 7-day cohort of its mobile shoppers. Every count is unique people, not sessions, and an order counts only if it came from a checkout started in the same 7 days.
What percentage of the shoppers who started checkout went on to complete an order?
Answer as a percentage, for example 50 or 50%, to 1 decimal place.
That was one exercise. Explore all 114, plus six interactive Metric X-Rays.
Get the KitWhat you will learn to talk about.
90 concepts, grouped by the questions a product team keeps asking. New to all this? Start with the 20 core ones.
Concepts by question
What should we build next, and why?
Strategy and Product Thinking
North-Star Metric, Product-Market Fit, RICE Scoring, Jobs-to-be-Done
34
Does it make money?
Revenue and Finance
Average Order Value, LTV, Contribution Margin, Runway
23
Do people come back?
Retention
Retention, Churn, Cohort Analysis, DAU/MAU
13
Did my change actually work?
Experimentation
A/B Test, Confidence Interval, Sample Size, P-value
11
How do people find it and get started?
Acquisition and Activation
Conversion Rate, CAC, Activation, Funnel Drop-off, Time-to-Value
9
What you will be able to do
- Explain what a metric means, and what it cannot tell you
- Check a number before you believe it
- Read a funnel and spot where people drop off
- Tell revenue from profit
- Judge whether an A/B test result can be trusted
- Pick a metric that fits what your design is trying to do
- Follow a product meeting, and join in
- Talk about your design’s impact with numbers, not adjectives
Built for people starting out
- 35
- concepts marked Beginner
- 22
- exercises marked Beginner
- 20
- core concepts to start with
- 6
- sector lenses, from e-commerce to fintech
Everything you just saw.
In one kit.
Product Designer’s Business Fluency Kit. Self-paced, in your browser.
90 concepts and metrics
114 graded exercises
6 interactive Metric X-Rays
Worked explanations and interpretation guidance
Self-paced, browser-based experience
Product Designer’s Business Fluency Kit
₹1,299
for the whole kit
Opens in your browser through your GLE account.
Independent expert review of the content is still pending. Progress is saved in this browser only; export a backup from the Progress page.
Questions designers ask first.
I’m a student or just starting out. Is this for me?
Yes. It assumes you can design screens, not that you have studied business. Every idea starts in plain words, 35 of the 90 concepts and 22 of the 114 exercises are marked Beginner, and a starting list of 20 core concepts shows you where to begin.
Do I need a business or maths background?
No. Beginner exercises use ratios and percentages, and every exercise has a worked solution. The 27 Advanced exercises ask for more careful reasoning, such as reading uncertainty in an experiment.
Is this a course or an interactive practice kit?
An interactive practice kit. It is built for doing rather than watching: you read a concept, calculate with numbers, and change the assumptions in a model, at your own pace.
Will it help me in interviews and my first job?
It does not promise a job. It gives you the vocabulary and the practice to follow product conversations and to talk about your design’s impact with numbers.
Do I need coding or analytics software?
No. It runs in your browser, and every exercise gives you the numbers it needs.
Does it use AI?
No. The kit does not use AI inference. Answers are checked by exact arithmetic against authored solutions, so the same answer always gets the same feedback.
Are the exercises graded?
Yes. Numeric answers are checked at the precision you give, and choice questions against the authored answer. Where the kit anticipates a common mistake, it tells you which one. Answer fields accept Indian formats such as 9,00,000.
Will my progress be saved?
Yes, in this browser on this device. The kit saves which concepts you opened, each exercise attempt (right or wrong, and the mistake pattern behind a wrong answer, up to the last 40 per exercise), whether you viewed a worked solution, and which X-Rays you opened. It does not save the numbers you type, and progress stays in this browser: another browser or device starts empty, and clearing site data or a private window removes it. Use Export on the Progress page to keep a backup file, and Import to restore it. Nothing is sent to GoodScool. The free exercise on this page is not saved.
Can I use it on mobile?
Yes. The kit has a layout designed for phones as well as desktop.
Know the number.
Make the decision.
Ninety concepts in plain words, 114 exercises and six X-Rays, in one browser-based kit. ₹1,299.