Analyze Profit Decline: Data Collection and Hypothesis Testing
You manage a coffee shop whose profits have recently declined. You need to diagnose the causes systematically and recommend next steps.
Constraints & Assumptions
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Compare the recent period to prior comparable periods and year-over-year to control for seasonality.
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Profit equals revenue minus COGS, labor, operating costs, fees, discounts, waste, and refunds.
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Consider in-store, mobile order-ahead, and delivery channels if available.
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Use a funnel view: traffic, conversion, average order value, margin, and cost.
Clarifying Questions to Ask
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When did the profit decline start, and is it one store or multiple stores?
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Did prices, menu, hours, staffing, suppliers, promotions, or local competition change?
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Are revenue, cost, labor, and channel data reliable and complete?
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Is the issue gross profit, operating profit, or cash flow?
Part 1 - Data Collection
What internal and external data would you collect?
What This Part Should Cover
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POS transactions, menu items, prices, costs, discounts, refunds, waste, labor schedules, hours, traffic, channel, loyalty, inventory, and supplier costs.
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Weather, holidays, local events, competitor openings, reviews, and macro conditions.
Part 2 - Metrics and Decomposition
What metrics and decompositions would you calculate?
What This Part Should Cover
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Revenue, orders, traffic, conversion, AOV, item mix, gross margin, labor cost per hour, waste, delivery fees, discount rate, and profit by channel.
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Contribution analysis to identify which factor explains the decline.
Part 3 - Hypotheses and Tests
What hypotheses would you test, and how would you test them?
What This Part Should Cover
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Demand decline, price/mix shift, cost increase, labor inefficiency, promo changes, delivery fee changes, supplier cost increase, competition, or seasonality.
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Statistical comparisons, regression, DiD if a change affected some stores or channels, and time-series analysis.
Part 4 - Validate and Act
How would you validate findings and propose next steps?
What This Part Should Cover
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Robustness checks, triangulation, small pilots, owner interviews, and operational audits.
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Action recommendations tied to the diagnosed driver.
What a Strong Answer Covers
A strong answer decomposes profit into revenue and cost drivers, gathers both internal and external data, tests concrete hypotheses, and recommends actions based on measured contribution.
Follow-up Questions
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What if revenue is flat but profit falls?
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How would you distinguish lower foot traffic from lower conversion?
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What would you test first if labor cost increased sharply?