Lighthouse

Level 8 · Boss: the customer economics one-pager

From Catherine Hale, Chief Executive Officer

“For the planning offsite I want one page on our customers: how many bought from us in 2025 and how many of them were new, what a buyer is worth in a year, and whether business accounts really matter as much as Megan says.”

Your goal

Step 1 of 3. Set result to a dict for 2025 with three ints: "buyers" (distinct customers with a booked order in 2025), "new_customers" (of those, customers whose first booked order ever is in 2025) and "returning_customers" (the rest).

Use the orders DataFramenot done yet
Use the order_items DataFramenot done yet
Store a dict in resultnot done yet

Step 1 · your code

Python

Loading the editor…

Reference solution

ResultPreview of orders · press Run to see yours

Preview of orders
order_id	customer_id	order_date	status	channel
1001	125	2023-01-01 20:51:19	completed	web
1002	156	2023-01-02 07:58:46	completed	web
1003	22	2023-01-02 10:25:27	completed	marketplace
1004	48	2023-01-02 11:21:51	completed	marketplace

Mote checks your result

Press Run. Each row that matches the goal becomes a firefly in your lantern.

Step 2 · your code

Python

Loading the editor…

Reference solution

ResultPreview of orders · press Run to see yours

Preview of orders
order_id	customer_id	order_date	status	channel
1001	125	2023-01-01 20:51:19	completed	web
1002	156	2023-01-02 07:58:46	completed	web
1003	22	2023-01-02 10:25:27	completed	marketplace
1004	48	2023-01-02 11:21:51	completed	marketplace

Mote checks your result

Press Run. Each row that matches the goal becomes a firefly in your lantern.

Step 3 · your code

Python

Loading the editor…

Reference solution

ResultPreview of order_items · press Run to see yours

Preview of order_items
order_item_id	order_id	product_id	quantity	unit_price
1	1001	121	9	31.99
2	1001	154	3	11.99
3	1002	154	4	11.99
4	1002	194	1	149.00

Mote checks your result

Press Run. Each row that matches the goal becomes a firefly in your lantern.

DataFrames

Loaded for you as pandas DataFrames, plus pd and np.

orders12,000 rows · 7 columns

order_idinteger
customer_idinteger
order_datetimestamp
statusvarchar
channelvarchar
shipping_feedecimal
coupon_codevarchar

First 5 rows of orders
order_id	customer_id	order_date	status	channel	shipping_fee	coupon_code
1001	125	2023-01-01 20:51:19	completed	web	0.00	NaN
1002	156	2023-01-02 07:58:46	completed	web	0.00	NaN
1003	22	2023-01-02 10:25:27	completed	marketplace	4.99	WELCOME10
1004	48	2023-01-02 11:21:51	completed	marketplace	4.99	WELCOME10
1005	82	2023-01-02 11:43:36	completed	web	0.00	WELCOME10

order_items30,338 rows · 6 columns

order_item_idinteger
order_idinteger
product_idinteger
quantityinteger
unit_pricedecimal
discount_pctdecimal

First 5 rows of order_items
order_item_id	order_id	product_id	quantity	unit_price
1	1001	121	9	31.99
2	1001	154	3	11.99
3	1002	154	4	11.99
4	1002	194	1	149.00
5	1002	193	2	19.99

returns1,673 rows · 5 columns

return_idinteger
order_item_idinteger
returned_ondate
reasonvarchar
refund_amountdecimal

First 5 rows of returns
return_id	order_item_id	returned_on	reason	refund_amount
1	14	2023-01-10	damaged	83.69
2	42	2023-01-10	wrong_item	19.99
3	105	2023-01-14	wrong_item	10.99
4	24	2023-01-16	changed_mind	26.99
5	126	2023-01-16	late	20.99

customers2,018 rows · 9 columns

customer_idinteger
first_namevarchar
last_namevarchar
emailvarchar
cityvarchar
statevarchar
signup_datedate
segmentvarchar
referral_sourcevarchar

First 5 rows of customers
customer_id	first_name	last_name	email	city	state	signup_date	segment	referral_source
1	Owen	Hudson	owen.hudson@icloud.com	San Francisco	CA	2022-06-02	consumer	search
2	Douglas	Mendoza	dmendoza69@gmail.com	Atlanta	GA	2022-06-02	consumer	NaN
3	Henry	Brooks	hbrooks@lakesidecafe.com	Los Angeles	CA	2022-06-04	business	NaN
4	Brian	Graham	bgraham@bluecedarhomes.com	Seattle	WA	2022-06-06	business	pinterest
5	Kyle	Jimenez	kjimenez27@yahoo.com	Indianapolis	IN	2022-06-07	consumer	NaN

products120 rows · 8 columns

product_idinteger
namevarchar
categoryvarchar
subcategoryvarchar
unit_pricedecimal
unit_costdecimal
launched_ondate
is_activeboolean

First 5 rows of products
product_id	name	category	subcategory	unit_price	unit_cost	launched_on	is_active
101	Vale Velvet Loveseat	Furniture	Sofas	1659.00	NaN	2023-09-11	true
102	Alder Oak Coffee Table	Furniture	Tables	919.00	503.50	2024-05-16	true
103	Orchard Rattan Dining Chair	Furniture	Chairs	789.00	429.87	2023-05-27	true
104	Upland Oak Bookcase	Furniture	Storage	429.00	214.70	2022-12-20	true
105	Avery Leather Bed Frame	Furniture	Beds	449.00	232.70	2021-08-31	true

employees60 rows · 8 columns

employee_idinteger
first_namevarchar
last_namevarchar
departmentvarchar
titlevarchar
manager_idinteger
hire_datedate
salaryinteger

First 5 rows of employees
employee_id	first_name	last_name	department	title	manager_id	hire_date	salary
1	Catherine	Hale	Executive	Chief Executive Officer	NaN	2016-03-01	285000
2	Robert	Kim	Executive	Chief Operating Officer	1	2017-01-09	235000
3	Megan	Collins	Sales	Head of Sales	1	2018-04-16	172000
4	Chloe	Gutierrez	Sales	Account Executive	3	2020-01-21	72000
5	Frank	Bell	Sales	Account Executive	3	2023-05-21	73000

web_sessions40,000 rows · 7 columns

session_idinteger
customer_idinteger
started_attimestamp
devicevarchar
sourcevarchar
pages_viewedinteger
convertedboolean

First 5 rows of web_sessions
session_id	customer_id	started_at	device	source	pages_viewed	converted
1	NaN	2023-01-01 23:02:24	mobile	paid	1	false
2	18	2023-01-01 15:07:49	desktop	paid	1	false
3	NaN	2023-01-01 16:55:46	desktop	direct	7	false
4	NaN	2023-01-01 12:43:28	mobile	organic	3	false
5	NaN	2023-01-01 13:06:21	mobile	social	2	false

marketing_spend3,276 rows · 3 columns

spend_datedate
channelvarchar
amountdecimal

First 5 rows of marketing_spend
spend_date	channel	amount
2023-01-01	paid	492.99
2023-01-01	email	37.38
2023-01-01	social	200.53
2023-01-02	paid	709.13
2023-01-02	email	64.13

The lesson

A leadership team asks the same three questions about customers every planning cycle: how many did we serve and how many were new, what is a customer worth in a year, and which customers carry the business. Each block in this level answers one of them, and each needs the definitions from this chapter: booked orders only, net revenue after discounts and refunds, a customer is new in the year of their first booked order.

Block 1: the base

Buyers in 2025 are distinct customers with a booked order that year. Splitting them into new and returning needs each customer’s first booked order over all years, not within 2025, otherwise every 2025 buyer looks new. Report the counts, not only the share: 641 new customers is a number a marketing plan can be built on.

Block 2: value per buyer

Three totals give three ratios: AOV (revenue per order), orders per buyer and revenue per buyer. The third is the product of the first two, which is a useful cross-check: if your revenue per buyer does not equal AOV times frequency, one of the denominators is wrong. Revenue per buyer in a year is also the building block of the predictive LTV from level 4.

Block 3: segments

Segment comparisons are customer metrics, so collapse orders to one row per customer before grouping by segment. Grouping orders directly by segment gives revenue per order, a different question. Put the revenue share next to the per-customer value: a segment can be worth six times more per customer and still be a minority of revenue, or, as here, be 15% of customers and more than half of revenue.

Common mistakes

Mixing windows. Blocks 1 and 2 are 2025; block 3 is 2023–2025. Say so on the slide.
Calling all buyers “customers acquired”. Returning buyers were acquired in earlier years and belong to those cohorts.
Averages without counts. A per-customer value means little until the reader knows how many customers it covers.

Interview note

Case interviews often end with “what would you put in front of the CEO?”. Three blocks, each with a number, its definition and one sentence of meaning, is a strong structure. Add the caveat that matters most: here, that a few business accounts carry the revenue, so losing one is a real risk.

Level 8 · Boss: the customer economics one-pager

Your goal

Step 1 · your code

Reference solution

Mote checks your result

Step 2 · your code

Reference solution

Mote checks your result

Step 3 · your code

Reference solution

Mote checks your result

What Catherine gets, and why

DataFrames

The lesson

Block 1: the base

Block 2: value per buyer

Block 3: segments

Common mistakes

Interview note

Lantern lit!

Level 8 · Boss: the customer economics one-pager

The request

Your goal

Step 1 · your code

Reference solution

Mote checks your result

Step 2 · your code

Reference solution

Mote checks your result

Step 3 · your code

Reference solution

Mote checks your result

What Catherine gets, and why

DataFrames

The lesson

What goes on a customer one-pager

Block 1: the base

Block 2: value per buyer

Block 3: segments

Common mistakes

Interview note

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