Chapter 20 — Exercises

Three tiers. 🪞 marks reflection; 🔄 marks retrieval.

Tier 1 — Recall and Comprehension

R1. State the six numbered claims from §20.1 with their verdicts. ⚠️ Which two are constantly conflated, and what's the difference between them?

R2. What does organic certification actually regulate? Give five provisions. ⚠️ Which one does §20.14 call underrated, and why?

R3. Name five pesticides permitted in organic production. ⚠️ Which one is persistent, accumulates in soil, and is being progressively restricted in the EU?

R4. What happened to rotenone, and what does its history demonstrate about the word "natural"?

R5. State the consistent findings of national pesticide residue monitoring programmes.

R6. ⚠️ Explain why the number of foods with "detectable residues" rose while actual residue quantities generally fell.

R7. What does the EWG's Dirty Dozen rank produce by, and what variable does it omit?

R8. Summarize the Stanford (2012) and Newcastle (2014) meta-analyses. ⚠️ Why are they less contradictory than they're usually presented as being?

R9. Why is the NutriNet-Santé organic-cancer association hard to interpret? Name five ways organic purchasers differ from non-purchasers.

R10. Give the environmental balance sheet from §20.8. ⚠️ What is the yield gap and why is it the crux?

R11. What did the NASEM 2016 report conclude? Name three other bodies that reached similar conclusions. ⚠️ What precisely does the ✅ verdict cover?

R12. Give the five legitimate GMO objections from §20.10. ⚠️ How many are safety objections?

R13. Explain the IARC/regulator split on glyphosate. Name two other things in IARC Group 2A.

R14. ⚠️ Rank the measured food risks from §20.12b. Where do monitored pesticide residues fall?

R15. What is the Bt irony?

Tier 2 — Application

A1. 🔄 Presence or dose? For each statement, say what it actually establishes and what you'd need to know to convert it into a claim:

a) "Glyphosate was detected in 43 out of 45 oat products tested." b) "The average person has over 200 industrial chemicals in their blood." c) "This sunscreen contains an ingredient classified as a possible carcinogen." d) "Organic strawberries had 92% fewer pesticide residues by weight." e) "There is formaldehyde in pears."

⚠️ Which of the five is closest to being a usable claim, and why?

A2. Marisol's trade, quantified. She spent $6.00 extra on organic apples and dropped broccoli, a bag of frozen peas, and a bunch of bananas.

a) Estimate the portions of produce lost. b) ⚠️ Estimate the reduction in residue exposure gained, using §20.4's findings. c) Write the sentence you'd say to her — using Chapter 17 §17.13's rules (compare, don't debunk; concede the true part; never make it about intelligence).

A3. Sort the reasons. For each stated reason for buying organic, assign it to health claim or values position, and give the honest verdict if it's a health claim:

a) "I don't want pesticides in my kids" b) "I don't like how conventional farming treats animals" c) "It has more antioxidants" d) "I'm worried about antibiotic resistance" e) "It's better for the planet" f) "It tastes better"

A4. The precautionary principle, applied symmetrically. §20.12 argues precaution must apply on both sides of the certification boundary.

a) Apply it to copper sulfate. What does precaution recommend? b) Apply it to a novel non-GM crop developed by mutation breeding. c) ⚠️ Construct a version of the precautionary principle that has a stopping rule. Is it still precautionary?

A5. Read the actual data. Find your country's most recent pesticide residue monitoring report. Pick one item you or your household buys.

A6. Values in a scientific costume. §20.10 argues the anti-GMO movement damaged its legitimate positions by arguing safety.

a) Name two other movements where the same thing happened. b) ⚠️ Find one you agree with. How would you restate its case without the borrowed science? c) What does a movement lose by doing that, strategically? Is the trade rational?

Tier 3 — Analysis and Synthesis

S1. The binary and the gradient. §20.13's closing box argues that category boundaries beat dose gradients commercially because a boundary lets you finish.

a) Test this against three other product categories — inside food or outside it. b) ⚠️ Design a marketing campaign for a dose-based claim. Why is it hard? c) Does this explain anything about why public health messaging underperforms? Be specific about the mechanism.

S2. The Dirty Dozen's net effect. §20.5 raises the possibility that the list reduces produce purchasing among people who can't afford organic.

a) Design the study that would establish this. Outcome, comparison, confounders. b) ⚠️ If it were established, what should EWG do? Does an advocacy organization have an obligation to measure the harm of its own messaging? c) Chapter 1 §1.5 asks what happens to a source's income if you decline. Apply it to EWG, and then to the organic industry, and then to a conventional produce trade association. ⚠️ Does applying it evenly change any of your conclusions?

S3. Two meta-analyses. §20.6 argues Stanford and Newcastle are largely not in conflict.

a) ⚠️ Argue that they ARE in conflict. What would have to be true? b) Why do two competent teams reach different emphases from overlapping literatures? Name three methodological choices that could do it. c) What would settle it, and why hasn't anyone run that study?

S4. Symmetric confounding, again. Chapter 19 §19.11 established that seed oil and UPF intake aren't separable. §20.7 makes a similar argument about organic purchasing.

a) ⚠️ Which confounding is worse? Defend your answer. b) Is there any dietary exposure in this book that is NOT confounded with socioeconomic status and health-consciousness? Name one, and say why it escapes. c) What does your answer imply about the entire observational nutrition literature?

S5. The yield gap. §20.8 calls this a genuine dilemma rather than a debunk.

a) State the strongest case that per-hectare metrics are the right ones. b) State the strongest case that per-kilogram metrics are. c) ⚠️ Does the answer depend on facts, or on values? If both, separate them explicitly.

S6. Write the honest label. Design a food label that communicates residue information accurately to a non-specialist shopper in under fifteen words.

a) Write it. b) ⚠️ Now write the version a competitor would use to undermine it. c) What does this exercise suggest about whether accurate risk communication can survive a competitive marketplace? What would have to change?

🪞 Reflection

M1. ⚠️ Did anything in this chapter make you uncomfortable in a way the previous two didn't? If so, name it. Was the discomfort about the evidence, or about a purchase you've been making?

M2. §20.14 asks you to know which reason you're buying organic for. Do you? ⚠️ If you've been telling yourself it's health and it's actually values, does the values reason survive on its own?

M3. The chapter says a values position that borrows a scientific costume gets taken down with the science. ⚠️ Have you done this? Not necessarily about food — about anything you care about.

M4. §20.12b points out that the measured food risks are dominated by things you can act on for free in your own kitchen. ⚠️ Do you own a meat thermometer? If not — and if you've ever paid an organic premium — sit with the arithmetic for a moment.

M5. 🔄 This is the fourth Part IV chapter where both sides agreed on the practical recommendation. ⚠️ What do you now think these public arguments are actually about? Write two sentences. You'll be asked again at the end of Chapter 22.