Decision Literacy Glossary
All the key words from our curriculum, explained in plain language. Terms are listed alphabetically. The Introduced column shows where each word first appears.
Age Fit
- Ages 8–9: Read terms aloud, use the examples, and let learners answer in speech or drawings.
- Ages 10–12: Use the definitions as written and connect them to the weekly lessons.
- Ages 12–15: Add counterexamples, edge cases, and real-world applications when terms feel too simple.
| Term | Definition | Introduced |
|---|---|---|
| 100 Times Test | A mental trick for evaluating risky choices: ask "If I did this 100 times, would I come out ahead overall?" It helps separate one-time luck from long-run patterns. | Week 9 |
| 5 Whys | A problem-solving technique where you ask "Why?" five times in a row to dig past surface symptoms and find the true root cause of a problem. | Week 15 |
| Anchoring | A mental shortcut where the first number or piece of information you hear sticks in your mind and pulls your judgment toward it, even if it has nothing to do with the real answer. | Week 5 |
| Availability bias | The brain's tendency to think that events are more common or likely if you can easily remember examples of them — like thinking plane crashes are common because they make the news. | Week 5 |
| Baseline | A starting measurement taken before you make a change, so you can tell whether the change actually helped. Without a baseline, you cannot know if things got better or worse. | Week 15 |
| Calibration | How closely your confidence level matches reality. A well-calibrated person who says they are "70% sure" turns out to be right about 70% of the time — not more, not less. Example: if you say you are 70% sure on 10 quiz answers, about 7 should be correct. | Week 3 |
| Commons | A resource that belongs to everyone and can be used by anyone — like a public park, a fishery, or a shared water supply. | Week 14 |
| Confidence level | A number (like a percentage) that shows how sure you are about something. Saying "I'm 80% confident" is more useful than just "I think so." | Week 3 |
| Confirmation bias | The tendency to search for, notice, and believe information that supports what you already think — while ignoring evidence that says the opposite. | Week 8 |
| Cooperation | Choosing to work with others toward a shared goal, even when you could act selfishly instead. In game theory, cooperation leads to better outcomes for everyone. | Week 13 |
| Coordination | Getting multiple people to act in sync so that everyone benefits — even without anyone being in charge. Difficult when people have different preferences or information. Example: a team agreeing where to meet after practice so nobody gets lost waiting. | Week 12 |
| Data collection | Systematically gathering information over time to test whether something is working. Good data collection means being honest about results, even when they are disappointing. | Week 17 |
| Decision quality | A measure of how good your thinking process was — not whether things worked out. A high-quality decision uses the best available information and clear reasoning, win or lose. Example: checking the forecast before bringing an umbrella can be high-quality even if it never rains. | Week 2 |
| Default action | What automatically happens if you do nothing or make no choice. A good decision protocol sets a smart default so that even your automatic behavior is helpful. Example: charging your phone outside your bedroom makes "leave it there overnight" the default. | Week 16 |
| Defection | In game theory, choosing to act selfishly instead of cooperating — usually because you are afraid the other person will take advantage of you. | Week 13 |
| Diminishing returns | Each extra unit of effort or information gives you a smaller and smaller benefit. The first hour of research is very helpful; the tenth hour barely moves the needle. | Week 10 |
| Endowment effect | The tendency to value something more highly just because you own it. People often demand more to give something up than they would pay to get it in the first place. | Week 6 |
| Escalation | Continuing to invest more resources into a failing plan because you have already put so much in — making the sunk cost fallacy worse over time. | Week 7 |
| Expected value (EV) | The average outcome you can expect if you made the same choice many times. Calculated by multiplying each possible outcome by its probability, then adding everything up. | Week 9 |
| Framing effect | How the way a choice is described changes how you feel about it — even when the facts are identical. "90% chance of surviving" and "10% chance of dying" are the same, but feel very different. | Week 6 |
| Frequency | How often something happens over many tries. Thinking in frequencies ("3 out of 10 times") is more reliable than thinking in vague labels like "sometimes" or "rarely." | Week 3 |
| Friction point | A specific moment or obstacle that regularly gets in the way of a good habit or decision. Finding your friction point is the first step to fixing it. | Week 15 |
| Heuristic | A mental shortcut your brain uses to make quick decisions without doing a full analysis. Heuristics are usually helpful but can cause systematic errors in certain situations. | Week 5 |
| Hindsight bias | The feeling — after you know how something turned out — that you "knew it all along." It makes bad luck look like bad decisions and good luck look like genius. | Week 4 |
| Hypothesis | A specific, testable prediction about what will happen if you try something. A good hypothesis lets you clearly say whether your experiment succeeded or failed. | Week 15 |
| Information diet | Being intentional about which sources of information you consume and how much time you spend gathering data — just like a food diet, but for what your brain takes in. | Week 10 |
| Interdependence | When your outcomes depend partly on what other people decide, and their outcomes depend partly on what you decide. Most real decisions involve some degree of interdependence. Example: in a group project, your effort changes everyone else's result. | Week 12 |
| Irreversible decision | A choice you cannot easily undo — a "one-way door." Irreversible decisions deserve more time, research, and caution than decisions you can reverse. | Week 11 |
| Iteration | Making a change, testing it, learning from the result, and improving. The process of getting better through repeated small improvements rather than trying to get everything perfect the first time. Example: moving a homework checklist from your backpack to your bedroom door after the first version failed. | Week 18 |
| Loss aversion | The human tendency to feel losses about twice as strongly as equivalent gains. Losing $10 feels worse than finding $10 feels good — this wiring affects many decisions. | Week 6 |
| Luck vs. skill | Luck is the part of an outcome caused by chance — factors outside your control. Skill is the part you can actually influence through better decisions and practice. Separating them helps you learn from results honestly. | Week 1 |
| Negative EV | When the expected value of a choice is below zero — meaning that on average, you will lose more than you gain. A choice with negative EV is not worth taking repeatedly. | Week 9 |
| Noise | Variation or randomness in information that does not tell you anything useful. The challenge is separating the signal (what matters) from the noise (what does not). Example: one especially chaotic morning might be noise, not a true pattern. | Week 10 |
| One-way door | A decision that is very hard or impossible to undo — like quitting a job, selling a house, or eating a meal. One-way doors require careful thinking before you walk through them. | Week 11 |
| Opportunity cost | The value of the best alternative you give up when you make a choice. Every choice has an opportunity cost, even when nothing feels like it is being sacrificed. Example: if you spend the afternoon gaming, you give up the chance to rest, practice, or see friends. | Week 11 |
| Outcome | The result of a decision — what actually happened. A good outcome does not always mean a good decision was made; luck plays a role too. | Week 2 |
| Positive EV | When the expected value of a choice is above zero — meaning that on average, you will gain more than you lose. Positive EV choices are worth taking repeatedly. | Week 9 |
| Positive-sum | A situation where cooperation makes everyone better off — the total gains are larger than if people acted selfishly. Not every situation is zero-sum. | Week 13 |
| Pre-mortem | Imagining that your plan has failed and then asking "what went wrong?" before you start. It helps you spot weaknesses before they become real problems. | Week 16 |
| Prediction | A statement about what you think will happen in the future, ideally with a confidence level attached. Predictions that get recorded and checked help you improve your thinking over time. | Week 1 |
| Prisoner's Dilemma | A classic situation in game theory where two people each do better by cooperating, but each is tempted to defect — and if both defect, both end up worse off than if they had cooperated. | Week 13 |
| Probability | The chance that something will happen, expressed as a number from 0 to 1 (or 0% to 100%). Thinking in probabilities means moving from "will it happen?" to "how likely is it?" | Week 3 |
| Process | The quality of your thinking and reasoning when making a decision — separate from whether things worked out. A good process means using the right information, considering alternatives, and reasoning carefully. | Week 2 |
| Protocol | A pre-decided set of steps to follow when a specific situation arises. Protocols take the guesswork out of recurring decisions so you do not have to rely on willpower in the moment. Example: "When I get home, I put my backpack on the desk and start a 25-minute timer." | Week 16 |
| Randomness | Events that happen by chance, with no predictable pattern or cause you can control. Understanding randomness helps you avoid blaming bad luck on bad decisions and vice versa. | Week 1 |
| Reasoning | The thinking you do to connect evidence to a conclusion. Recording your reasoning before an outcome lets you evaluate whether your process was good, regardless of results. Example: "I chose the earlier bus because it is more reliable, even though it leaves sooner." | Week 2 |
| Reflection | Looking back at past decisions to understand what worked, what did not, and what you would do differently. Systematic reflection is how decision-makers improve over time. | Week 4 |
| Regulation | Rules or agreements that manage how a shared resource is used, to prevent overuse and protect it for future use. Example: a class agreement that everyone refills shared markers before opening a new box. | Week 14 |
| Representativeness | A mental shortcut where you judge how likely something is by how closely it matches a typical example in your mind — even when the actual probability says otherwise. | Week 5 |
| Reversible decision | A choice you can easily undo if it does not work out — a "two-way door." Reversible decisions can be made more quickly because the cost of being wrong is low. | Week 11 |
| Ripple effect | When one decision causes a chain of further consequences — like a stone dropped in a pond. Good decision-makers try to anticipate second and third ripples, not just the immediate splash. | Week 12 |
| Root cause | The underlying reason a problem keeps happening — not just the visible symptom. Fixing a root cause solves the problem; treating a symptom only hides it temporarily. | Week 15 |
| Scarcity bias | The tendency to want something more when it seems rare or limited — "only 3 left!" — even when the scarcity is artificial. Often used in advertising to create urgency. | Week 8 |
| Second-order effects | The consequences of consequences — what happens as a result of what happens. Good decisions think beyond the immediate outcome to these downstream ripples. | Week 12 |
| Signal | Information that genuinely tells you something useful and should influence your decision. The challenge is finding the signal hidden in all the noise around you. Example: five straight late departures is more signal than one unusually messy morning. | Week 10 |
| Social proof | The tendency to do what other people are doing, assuming that popularity means correctness — "5 million happy customers can't be wrong." A common but unreliable shortcut. | Week 8 |
| Sunk cost | Money, time, or energy you have already spent and cannot get back. Because it is gone regardless of what you do next, it should not influence future decisions. | Week 7 |
| Sunk cost fallacy | The mistake of continuing a bad plan because you have already invested in it — letting past costs influence future decisions even though those costs are gone forever. | Week 7 |
| Sustainability | Using a shared resource at a rate that allows it to replenish, so future users can benefit too. | Week 14 |
| Tragedy of the commons | What happens when individuals acting in self-interest overuse a shared resource and destroy it for everyone — even though no single person intended that outcome. | Week 14 |
| Trigger | A specific situation or signal that tells you to follow your protocol. For example, "When I feel the urge to quit, I will ask the magic question before deciding." | Week 16 |
| Two-way door | A decision you can reverse if it turns out to be wrong — like trying a new route to school or ordering something new at a restaurant. Two-way doors allow for experimentation. | Week 11 |
| Uncertainty | Not knowing for sure what will happen. All decisions involve some uncertainty; the skill is making good choices despite it, not waiting for certainty that may never come. | Week 1 |
| Walk-away point | A pre-decided limit — a specific loss, time, or cost — at which you will stop and move on, no matter how tempting it is to keep going. Setting it in advance protects against the sunk cost trap. | Week 7 |
| Zero-sum | A situation where one person's gain exactly equals another person's loss — the total stays the same no matter what. Not every situation is zero-sum; many allow for cooperation and mutual gain. | Week 13 |