Problem Definition
Your client is the Canadian Wildlife Federation (CWF). This government affiliated non-profit organization aims to educate Canadians about wildlife and promote responsible human actions and conservation.
One particular endangered species population, the swift fox, has been declining dramatically.
CWF has contacted your firm to help them figure out what is causing this population decline and what they can do to stop it from declining any further.
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- Swift fox populations were historically stable until this past year
- No specific targets for the population recovery
- The swift fox is an omnivore
- Environmental factors have remained relatively unchanged over time
- CWF is particularly concerned with a new outbreak of a deadly gastrointestinal disease that has affected several forests of Canada, including the habitat of the swift fox
- There are no hunting licenses for swift foxes
Question 1Structuring
What factors would you consider to answer the client's questions?
Hint · Structuring
Build 3–4 branches that are specific to this client and question, not a generic framework. Check they don't overlap and together cover the problem.
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-
Fewer births
- a. Deterioration in health factors
- b. Increase in gender imbalance
-
More deaths
- a. Increase in hunting
- b. Shortage of food, water or shelters
- c. Increase in occurrence of diseases
-
Increased net migration (departures - arrivals)
- a. Destruction or change of habitat
- b. Increase in human interference
What the interviewer is looking forShow guidanceHide guidance
Allow the candidate to take time to structure their thinking. The key is to identify the three main drivers of population change: births, deaths, and migration. A strong answer will break each driver into sub-factors.
Question 2Judgement & Insights
The swift fox population was separated into four groups (clouds) by the construction of new interprovincial highways five years ago. We have gathered the following data about the swift fox population habitat and demographics, for each of these four groups [share Exhibit 1 and Exhibit 2].
Hint · Judgement & Insights
Read the exhibit title, axes and units first. Lead with the ‘so what’, then back it with one or two numbers.
What can you conclude from these exhibits?
Exhibit 1Current swift fox population habitat
The swift fox habitat is divided into four quadrants by two intersecting interprovincial highways:
| West | East | |
|---|---|---|
| North | Group A | Group C |
| South | Group B | Group D |
Two highways cross through the habitat, creating four separated zones. Group A is in the northwest, Group C is in the northeast, Group B is in the southwest, and Group D is in the southeast.
Source: Canadian Wildlife Federation case file
Exhibit 2Swift fox demographics for the four groups
| Group | Fraction of population | Percent male | Percent female | Population affected by disease (%) |
|---|---|---|---|---|
| A | 1/4 | 10% | 90% | 25% |
| B | 1/8 | 30% | 70% | 40% |
| C | 3/8 | 50% | 50% | 10% |
| D | 1/4 | 40% | 60% | 5% |
Source: Canadian Wildlife Federation case file
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Exhibit 1 illustrates how the four groups are organized around the new interprovincial highways, and Exhibit 2 compares the populations of each group in terms of population size, gender and disease spread.
Several key insights can be drawn from these:
- The gender distribution is unbalanced. Only one group has a 50-50 distribution. Groups A, B and D have more females than males.
- The highway has disproportionately split the population, which may have impacted the gender imbalance and in turn, the birth rate.
- The rate of disease is inconsistent and seemingly high for three of the four groups. This could be related to the environment on either side of the highway.
- There is no correlation between the rate of disease and the size of population or gender balance.
- It is not clear what has caused the gender imbalance -- maybe males travel further away and are more likely to be killed crossing the highways?
The population decline seems to be due to the spread of the disease and gender imbalance within groups. Additional analysis would be required to investigate the nature of the disease, methods for disease reduction, and ways to rebalance the gender mix.
What the interviewer is looking forShow guidanceHide guidance
Share Exhibit 1 and Exhibit 2 with the candidate. Look for the candidate to identify key patterns and insights from the data, including gender imbalance, disease rates, and the impact of highway construction on population segmentation.
Question 3Numeracy
The client is intrigued by what you found in the exhibits and is really curious to understand how impactful the disease and gender disparity are on the overall population.
Hint · Numeracy
Write the formula before you plug in numbers, keep units and zeros explicit, and sanity-check the order of magnitude at the end.
By how much would you expect the population to decline next year, based on these two issues?
Additional InformationAsk for more dataHide data
- There are 5,000 swift foxes
- Swift foxes choose only one mate for life
- Mating season occurs once per year (1 litter is born), but pairs mate once every five years
- Diseased foxes can give birth
- The average fox litter yields 1.5 foxes
- All deaths not caused by disease are natural
- Life expectancy is 10 years, but foxes with the disease only live one year
- Net migration is zero
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Population change = New births next year - Deaths next year
New births next year = Number of pairs possible x Average birth per pair per year
Average birth per pair per year = Number of births per litter x Total litters per life / Life expectancy = 1.5 x 2 / 10 = 0.3
The number of possible pairs is constrained by the lower sex percentage (i.e., if there are only 10 males and 90 females, there can only be 10 pairs).
| Group | Fraction of population | Total population | Lower sex percentage | Number of pairs possible |
|---|---|---|---|---|
| A | 1/4 | 1,250 | 10% | 125 |
| B | 1/8 | 625 | 30% | ~190 |
| C | 3/8 | 1,875 | 50% | ~940 |
| D | 1/4 | 1,250 | 40% | 500 |
| Total | ~1,750 |
New births next year = 1,750 x 0.3 = 525
Deaths next year = Deaths by disease next year + Natural deaths next year
Natural deaths next year = Healthy population / Life expectancy
| Group | Total population | % diseased | Deaths by disease | Healthy population |
|---|---|---|---|---|
| A | 1,250 | 25% | ~310 | 940 |
| B | 625 | 40% | 250 | 375 |
| C | 1,875 | 10% | ~190 | 1,685 |
| D | 1,250 | 5% | ~60 | 1,190 |
| Total | ~810 | ~4,190 |
Natural deaths next year = (940 + 375 + 1,865 + 1,190) / 10 = ~420
Population change = 525 - 810 - 420 = -705 = ~14% of the current population
14% decline next year is a highly concerning rate. The number of natural deaths is smaller than the number of births. Without the disease, the population would be essentially stable, growing by 0.5% (525 - 500 = 25)/5,000, which seems acceptable.
The decline in fox population can be overcome by reducing the disease-related deaths and increasing births. To reduce disease-related deaths, CWF should identify cures to the gastrointestinal disease, separate diseased foxes from the rest to avoid contamination, and identify and eliminate the source of the disease. To increase births, CWF should look into the causes of the gender imbalance, and address them so that male population can be restored in groups A, B and D.
What the interviewer is looking forShow guidanceHide guidance
Share the additional information if asked by the candidate. The candidate should work through the math step by step, calculating births and deaths separately to arrive at the net population change.
Question 4Synthesis
The chairman of the Canadian Wildlife Federation has an upcoming public statement and would love to include a few pieces of insight to update the local community on plans to save the swift fox. She has asked you to provide a thirty second synopsis of key findings, so that she can share them in her public statement.
Hint · Synthesis
Answer first: the recommendation, two or three reasons with numbers, then risks and next steps.
What would you tell her?
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You have asked us to investigate what is causing the dramatic decline in the swift fox population, and investigate potential solutions.
We have found that fox population is declining at a rate of 14% each year mostly due to a gastrointestinal disease that is reducing life expectancy from 10 years to 1 year and of gender imbalance.
In the next couple weeks, we will run several additional analyses to refine our recommendations. First, we will create a cure and eradicate plan and identify the capital and time that would be required. Second, we will analyze the root cause of the gender imbalance to establish a rebalancing strategy.
Contributed by CaseDrill practice community
What the interviewer is looking forShow guidanceHide guidance
Look for a concise, structured response that covers the key findings and next steps. The candidate should lead with the main finding, provide supporting evidence, and outline recommended actions.