Evaluate a Bhopal tutoring reminder
Before the decision
Attendance rose after a reminder pilot launched alongside a timetable change. The pilot began in the same month the centre moved classes to later hours. Tutors have anecdotal support for both explanations and want a study that can separate them.
The problem
Should the team choose Personal reminders or Generic reminders for the next 12 months?
Decision owner: The business unit lead.
Before-and-after results mix the effects of the reminders and timetable.
Option economics
Scroll the table to see all figures.
| Option | Volume (attended sessions) | ₹ per unit | Fixed cost | Net contribution |
|---|---|---|---|---|
| Personal reminders | 58,500 | 75 | ₹24.5 lakh | ₹19.38 lakh |
| Generic reminders | 54,400 | 67 | ₹17 lakh | ₹19.45 lakh |
Make the call
- Calculate net contribution for Personal reminders and Generic reminders. Which assumption makes the comparison most fragile?
- If the leading option delivers 10% fewer attended sessions, does your recommendation change?
- What evidence would you ask for before the team makes an irreversible commitment?
Reveal the worked solution
Start by validating Generic reminders. It contributes ₹19.45 lakh after fixed costs and leads by ₹0.07 lakh. Treat that gap as the amount of unmodelled cost or lost contribution the option can absorb before the ranking reverses.
- Frame the decision
Specify the eligible population and the outcome before collecting data. Treat the figures as planning estimates. Use comparable groups to measure the effect before rollout.
- Calculate both options
Personal reminders: 58,500 attended sessions × ₹75 less ₹24.5 lakh in fixed costs gives ₹19.38 lakh. Generic reminders: 54,400 attended sessions × ₹67 less ₹17 lakh in fixed costs gives ₹19.45 lakh.
- Stress-test the forecast
Generic reminders leads by ₹0.07 lakh in the base case. If Generic reminders delivers 10% fewer attended sessions (48,960) at the same margin and fixed cost, it contributes ₹15.8 lakh. Holding the other option constant, the stressed result falls behind. This isolates volume risk. Check whether both options would respond to the same change in demand.
- Set a decision threshold
Holding the other option’s result fixed, Generic reminders needs at least 54,292 attended sessions to match or beat it under the model. Randomise within timetable blocks and compare attendance by assigned arm.
Before-and-after results mix the effects of the reminders and timetable. Compare the cost of a limited test with the loss the business would face if the full commitment failed. Ask the team to agree the decision criterion before collecting more evidence.
Check whether your answer names the trade-off, cites a number from the exhibit and specifies a reversal condition.
What if the whole market moves?
The worked solution tests a change to one option at a time. Here, both options gain or lose the same percentage of volume. Unit contribution and fixed costs stay constant.
| Volume scenario | Personal reminders | Generic reminders | Higher contribution |
|---|---|---|---|
| Both lose 10% of volume | ₹14.99 lakh | ₹15.8 lakh | Generic reminders |
| Base assumptions | ₹19.38 lakh | ₹19.45 lakh | Generic reminders |
| Both gain 10% of volume | ₹23.76 lakh | ₹23.09 lakh | Personal reminders |
Explain which option you would take forward. Check whether capacity, price or customer mix would also change as the market moves.
Practise this case as an interview