Angela's Tools · Chapter 29 · Engineering Solutions for Protecting Ecosystems
Lab 3 of 3 · Recording sheet
Bats, Pigs and People: Choosing a Plan to Prevent Nipah
Investigation question: Fruit bats near Green Valley's pig farms can carry Nipah virus, but the same bats pollinate fruit trees and spread forest seeds. With $6 million for ten years, which plan or package should the district choose to protect people, the bats and farm families, and does the answer hold up when different people's priorities are weighted and the estimates turn out worse than expected?
Data-driven decisionGroups of 41 session
Setup 5 · Activity 50 · Cleanup 3 min
MS-LS2-5 · assessesMS-ETS1-2 · assesses
NameGroupDate
Your role today
- Pig farmer and facilitator: Speaks for the district's 60 pig farms, keeps the discussion moving and makes sure every stakeholder speaks before the group agrees on weights.
- District health officer and recorder: Speaks for farmworkers and their families and records the agreed weights, the score matrix and the totals.
- Durian orchard grower and checker: Speaks for the fruit growers whose trees bats help pollinate and checks every score against the scoring rules and every multiplication.
- District budget officer and timekeeper: Speaks for the district's $6 million fund, keeps the group on schedule and confirms that any package stays within budget.
Safety
- Paper-only activity: the only physical hazards are paper edges and scissors. Use blunt-tip scissors if students cut their own weight chips.
- The case involves a disease that has killed people. Some students may have family experience of serious illness or of farming; keep the discussion about evidence and choices, not about blame, and let students step out of a role if it is uncomfortable.
- Stakeholder roles are perspectives, not judgments of real people or places; the district is invented.
Procedure
- Read the background and both data tables aloud as a group, one section per stakeholder. Each stakeholder underlines the numbers their person cares about most.
- Stakeholder case (5 minutes). Read your card. Lay out your 20 weight chips (5 points each) to match your stakeholder's weights, prepare a 30-second case for your top criterion, and answer q1.
- Negotiate (10 minutes). Put everyone's chips on the table. The facilitator asks each stakeholder for their 30-second case. Agree on one set of weights that totals 100 and that every member can accept, record it in the weights table and answer q2.
- Score (8 minutes). Use the scoring rules to turn each single plan's data into a score from 0 to 4 on each criterion and fill the score matrix (q3). The checker confirms every score against the rules.
- Compute. For each plan, multiply each score by its weight and add the six products. Do it first with the practice weights (q4), then with your agreed weights; split the four stakeholder columns among the group so the totals table is complete (q5, q6).
- Package. Choose one package from the package table, score it with the same rules and compute its total with the practice weights and with your agreed weights (q7).
- Worst-case check. Rescore human health for plans A and B and for your package using the top of each likely range, and recompute their practice-weight totals (q8).
- Recommend. Write the group's recommendation to the district council (q11), post your weights, winners and package on the class chart, and answer the remaining questions on your own.
Record your observations
Lab 3 recording sheet: Bats, Pigs and People
About this case — Green Valley District is invented, and every number in the two data tables is a teaching estimate. The background facts about Nipah virus and fruit bats are real.
Background. Large fruit bats called flying foxes are the natural host of Nipah virus; infected bats usually do not get sick. In Malaysia and Singapore in 1998 and 1999, pigs on farms with fruit trees caught the virus, most likely from bitten fruit and saliva that feeding bats dropped into the pens, and passed it to the people who worked with them. More than 300 people fell ill and more than 100 died, and more than a million pigs were killed to end the outbreak. Since 2001, people in Bangladesh and India have caught it mostly from fruit or raw date palm sap that feeding bats contaminated, and it can also spread from person to person. There is still no approved vaccine or medicine for people. Health agencies advise protecting pig feed and pig sheds from bats and thinking about bats when choosing where to build a pig farm. Fruit bats are valuable too: flying foxes help pollinate durian, one of Southeast Asia's most valuable fruit crops, and carry the seeds of many forest trees. Bat experts warn that chasing a roost away can simply move the bats to other trees, and there is no evidence that killing or chasing bats stops Nipah from spreading.
Green Valley District. The district has 60 pig farms, durian and other fruit orchards, and a forest roost of about 15,000 flying foxes 2 km from the nearest farms. Last year Nipah virus was found in pigs in a neighboring district. The health office estimates that with no action, the chance of a Nipah outbreak in people here within 10 years is about 40 percent. The district has $6 million to spend over 10 years.
Five single plans (science team estimates; teaching data)
Simulated teaching dataset: the numbers are invented to be realistic, not measured.
| Plan | 10-year cost ($ million) | Chance of an outbreak in people in 10 years (%) | Likely range (%) | Bat colony kept (%) | Farm income kept (%) | Who pays or loses | Certainty of the estimate |
|---|
| A. Move pig pens away: farms within 1 km of the roost move their pens, and no fruit trees grow within 50 m of any pen | 4.5 | 6 | 3 to 10 | 100 | 93 | Pig farmers lose some income for 2 years while they move; the district pays moving costs | Medium-high |
| B. Bat-proof the sheds: wire-mesh netting over pens and roofs over feed troughs | 2.5 | 15 | 8 to 30 | 100 | 98 | Each farm pays about $50 a year to keep the nets repaired | Medium |
| C. Remove the roost: cut the roost trees and drive the bats away with noise | 1.0 | 30 | 10 to 60 | 10 | 85 | Orchard owners lose part of their harvest for good, with no payment | Low |
| D. Protect workers and catch outbreaks early: gloves, masks and training; fast testing of sick pigs; quarantine of infected farms | 1.5 | 25 | 15 to 35 | 100 | 90 | No one loses income; culled pigs are paid for | Medium-high |
| E. Feed the bats elsewhere: plant figs and other fruit trees by the forest, far from farms, plus a radio and school campaign | 0.8 | 35 | 20 to 45 | 100 | 100 | No one | Low |
Two-plan packages within the budget (science team estimates; teaching data)
Simulated teaching dataset: the numbers are invented to be realistic, not measured.
| Package | 10-year cost ($ million) | Chance of an outbreak in people in 10 years (%) | Likely range (%) | Bat colony kept (%) | Farm income kept (%) | Who pays or loses | Certainty of the estimate |
|---|
| A + D | 6.0 | 3 | 2 to 6 | 100 | 93 | Pig farmers lose some income while moving | Medium-high |
| A + E | 5.3 | 5 | 2 to 9 | 100 | 93 | Pig farmers lose some income while moving | Medium-high |
| B + D | 4.0 | 8 | 4 to 15 | 100 | 98 | Farms pay to keep nets repaired | Medium-high |
| B + E | 3.3 | 10 | 5 to 22 | 100 | 98 | Farms pay to keep nets repaired | Medium |
| C + D | 2.5 | 18 | 8 to 40 | 10 | 80 | Orchard owners lose part of their harvest for good, with no payment | Low |
| D + E | 2.3 | 20 | 12 to 32 | 100 | 90 | No one | Medium |
Package A + B ($7.0 million) is over budget. Combined chances are the science team's estimates; they are not found by adding or multiplying the single-plan numbers.
Scoring rules (0 = worst, 4 = best)
| Criterion and what the score is based on | 4 | 3 | 2 | 1 | 0 |
|---|
| Human health: chance of an outbreak in people (%) | 10 or less | 11 to 20 | 21 to 30 | 31 to 40 | over 40 |
| Bats and their services: bat colony kept (%) | 95 or more | 75 to 94 | 50 to 74 | 25 to 49 | under 25 |
| Farm income kept (%) | 98 or more | 93 to 97 | 88 to 92 | 80 to 87 | under 80 |
| Low cost: $ million over 10 years | 1.0 or less | 1.1 to 2.0 | 2.1 to 3.5 | 3.6 to 5.0 | 5.1 to 6.0 |
| Fairness: who pays or loses | No one loses income | Users pay a small cost, or a group loses some income for 3 years or less | A group loses income for good but is paid | A group loses income for good with no payment | |
| Certainty: the science team's rating | High | Medium-high | Medium | Low | |
Stakeholder cards
1 Pig farmer (farm income 35, fairness 25, human health 15, cost 10, certainty 10, bats 5)Your family raises 400 pigs. Moving your pens would mean two hard years, and an outbreak would mean losing your whole herd. You want your workers safe, but you cannot afford a plan that sinks the farm.
2 District health officer (human health 45, certainty 20, farm income 10, cost 10, fairness 10, bats 5)In the 1998-1999 outbreak more than 100 people died, and there is still no vaccine or medicine. Your job is to keep farmworkers and their families safe, and you want a plan you can count on.
3 Durian orchard grower (bats and their services 35, farm income 25, human health 15, fairness 10, certainty 10, cost 5)Your durian trees are your income, and flying foxes help pollinate their flowers at night. Getting rid of the bats might sound simple, but it could shrink your harvest for good.
4 District budget officer (cost 40, human health 20, certainty 15, farm income 10, fairness 10, bats 5)The $6 million must last ten years, and the same fund pays for roads and clinics. You want the most protection for each dollar and no surprises.
Weights (each column totals 100)
| Criterion | Practice set | Pig farmer | Health officer | Orchard grower | Budget officer | Our agreed weights |
|---|
| Human health | 30 | 15 | 45 | 15 | 20 | |
| Bats and their services | 20 | 5 | 5 | 35 | 5 | |
| Farm income | 15 | 35 | 10 | 25 | 10 | |
| Low cost | 15 | 10 | 10 | 5 | 40 | |
| Fairness | 10 | 25 | 10 | 10 | 10 | |
| Certainty | 10 | 10 | 20 | 10 | 15 | |
| Total | 100 | 100 | 100 | 100 | 100 | |
1.Your stakeholder's case: name their top criterion and give one number from the case file that shows why it matters to them.
2.How did your group reach its agreed weights? Name one compromise a stakeholder made and why they accepted it.
3.Score matrix: use the scoring rules to score each single plan from 0 to 4 on each criterion.
| Human health | Bats and their services | Farm income | Low cost | Fairness | Certainty |
|---|
| A. Move pig pens away | | | | | |
| B. Bat-proof the sheds | | | | | |
| C. Remove the roost | | | | | |
| D. Protect workers, catch outbreaks early | | | | | |
| E. Feed the bats elsewhere | | | | | |
Weighted totals (score × weight, added across the six criteria)
| Plan | Practice weights | Our agreed weights | Pig farmer | Health officer | Orchard grower | Budget officer |
|---|
| A | | | | | | |
| B | | | | | | |
| C | | | | | | |
| D | | | | | | |
| E | | | | | | |
| Package: ______ | | | | | | |
Analysis questions
4.Compute each single plan's total with the practice weights (human health 30, bats 20, farm income 15, cost 15, fairness 10, certainty 10). Show the work for one plan and rank all five.
5.With your group's agreed weights, which single plan ranks first? Is it the same as with the practice weights? Explain which weight made the difference.
6.Use the four stakeholder columns. Which single plan wins for each stakeholder? What pattern do you see, and what does it tell you about where disagreement comes from?
7.Score your chosen package with the scoring rules and compute its total with the practice weights and with your agreed weights. Does it beat the best single plan? Show the scores.
8.Worst-case check: rescore human health for plans A and B and for your package using the top of each likely range, then recompute their practice-weight totals. Which wins now, and what should the district learn from this?
9.Plan C removes the bats, the animals that carry the virus, yet it ranks last. Use at least two criteria to explain why, and name the ecosystem services the district would lose.
10.Which parts of your recommendation came from science (data and predictions) and which came from values (weights)? Give one example of each.
11.Write your recommendation to the district council: the plan or package, two pieces of evidence from your matrix, the tradeoff you accept, and what the district should monitor to know whether the plan is working.
12.Describe one way the scoring rules could mislead the district, using an example from the data tables.