Facts, Opinions, and Testable Claims

By Better Wise

A Sentence Worth Interrogating

Every verification starts the same way. Someone says something, and you decide what kind of thing you just heard. "The bridge reopened on Tuesday." "That bridge is ugly." "The new bridge will cut commutes by 20 percent." Three sentences, three different jobs, and only one of them can be settled by evidence unless you first untangle them.

This is lesson one of the course, so nothing here assumes prior training. It gives you the labeling habit that everything else builds on.

By the end of this lesson you can:

• Tell a fact, an opinion, and a testable claim apart in a single pass.
• Ask the one question that separates checkable statements from background noise.
• Rewrite a vague statement into something evidence could confirm or refute.
• Name the specific evidence that would settle a given claim.

Fact, Opinion, or Claim You Can Check

Three Labels, One Quick Test

• Fact: a statement that is verifiable, and that evidence already settles. "The pharmacy on Fifth Street closes at 7 p.m." Check the posted hours and you are done.
• Opinion: a statement that expresses a preference, value, or evaluation. "7 p.m. is too early." No measurement will settle it, because it is about what someone wants, not about what is.
• Testable claim: a specific assertion about the world that evidence could confirm or refute. "Extending pharmacy hours to 9 p.m. would raise late prescriptions filled by 15 percent." This is checkable, you just have not done the checking.

flowchart TD
    S["🗣️ Statement"] --> Q{"Could evidence<br/>settle it?"}
    Q -->|No, it is a preference or value| O["💭 Opinion"]
    Q -->|Yes| Q2{"Already settled?"}
    Q2 -->|Yes| F["📌 Fact"]
    Q2 -->|No, or disputed| C["🔍 Testable claim"]

One warning before you start labeling everything: these labels are a tool, not a trophy. Facts are really claims with very strong evidence behind them, which is why yesterday's fact sometimes gets revised. And the labels get abused in both directions. Advertisers dress opinions as facts, and cynics wave off checkable claims as "just opinions." Your job is to sort the sentence, not to win the argument.

Practice. Label each one, then say in a few words what evidence would settle the part that can be settled.

1. "The museum's new wing opens on March 3."
2. "The new wing is the best thing this museum has ever built."
3. "The new wing will draw 40,000 visitors in its first month."
4. "Everyone in town loves the new wing."
5. "Museums matter more than hospitals."

Click to reveal guidance

1. Fact. Verify with the museum's opening announcement.
2. Opinion. "Best" is an evaluation, though it may rest on factual premises about cost or design.
3. Testable claim. Count the turnstile entries in the first month.
4. Almost a claim, but too vague to check. Who counts as "everyone"? A survey of a defined group with a stated result would make it testable.
5. Opinion, but it hides testable premises about funding, attendance, and health outcomes. Split it and test the premises.

The Two-Sided Test: What Would Prove It Wrong?

Ask two questions about any claim:

• What would I expect to see if this were true?
• What would I expect to see if it were false?

If both answers come out identical, you do not have a claim yet, you have a mood. "This app makes you more productive" fails the test until you pin down productive at what, measured how, over what period, compared with whom. Rewrite it as "Users who install the app finish their weekly reports 20 percent faster than users who do not," and now both sides exist: faster or not faster, on reports, inside a time frame.

A claim that no possible observation could contradict is unfalsifiable. "It works for anyone who truly believes in it" cannot fail, which means it asks for trust instead of evidence.

Watch for authority gestures that carry no content: "studies show," "experts agree," "many people say." Each one is a promise of evidence with the evidence removed: no named study, no count, no comparison.

Practice. Rewrite each statement so that evidence could confirm or refute it. Name the number, the group, or the comparison.

1. "Our customer service is much better now."
2. "Studies show this mattress improves sleep."
3. "Nobody wants to work anymore."

Click to reveal one acceptable rewrite each

1. "Average response time to support emails fell from 30 hours to 4 hours between January and June, according to our ticket logs."
2. "In a study of 60 adults, participants on this mattress fell asleep 12 minutes faster than on their previous mattress, measured by sleep trackers." The point is to demand the study, the group, and the measurement, not to accept the phrase "studies show."
3. "The share of job postings filled within 30 days fell from 70 percent to 55 percent in 2024." Any rewrite with a defined measure and period works, because it can now fail.

Several valid rewrites exist for each. What matters is that your version has a wrong answer available.

When an Opinion Wears a Lab Coat

Some sentences are stacked. "This phone is a waste of money because the battery dies before noon" carries an evaluation ("waste of money") sitting on a factual claim ("battery dies before noon"). You cannot test the evaluation, but you can absolutely test the battery claim with a standardized rundown test.

The reverse also happens, and it is worth respecting. "The library should open later because students study past 6 p.m." is a value conclusion supported by a factual premise. You cannot settle "should," but you can check how many students actually study past 6 p.m. An opinion with checkable premises is not irrational. It is an argument waiting for its evidence.

Practice. Split each sentence into its evaluation and its checkable part, then name one piece of evidence for the checkable part.

1. "This phone is a waste of money because the battery dies before noon."
2. "The city's new bike lanes are dangerous, and crashes have doubled."

Click to reveal guidance

1. Evaluation: waste of money. Checkable: battery life before noon. Evidence: a timed, repeatable battery test on a full charge.
2. Evaluation: dangerous. Checkable: crashes doubled. Evidence: crash reports from the same streets over comparable periods before and after the lanes went in.

Quick self-check before you move on:

A statement that expresses a preference or value, rather than something evidence could settle, is an _____. A _____ is a specific assertion about the world that evidence could confirm or refute. The question that does the most work in this lesson is: what _____? A claim that no possible observation could contradict is called _____. "Studies show" is a red flag because it hides the _____ and the _____.

Newsroom Habits Before You Believe Anything

• Label the sentence before you judge it. Most bad arguments survive because nobody asked what kind of statement was being made.
• Ask "what would settle it?" out loud, in those words. It converts a debate into a task.
• Treat "studies show" and "everyone knows" as placeholders. Replace them with a source or set them aside.
• Do not dismiss every opinion. Check the factual premises underneath it, then argue about values honestly.
• Keep a healthy doubt of your own labels. If you call something "just an opinion" because you dislike it, you have stopped verifying and started defending.

Front: What is a fact? Back: A statement that is verifiable and already settled by evidence, independent of anyone's preference.

Front: What makes a statement an opinion? Back: It expresses a preference, value, or evaluation, so evidence cannot settle it as true or false.

Front: Define testable claim. Back: A specific assertion about the world that evidence could confirm or refute.

Front: What is the core question to ask about any claim? Back: What evidence would settle it?

Front: What are the two sides of the two-sided test? Back: What would I expect to see if this were true, and what if it were false?

Front: What does it mean when a claim's true and false predictions look identical? Back: The statement is not yet checkable; it needs specificity before it can be tested.

Front: What is an unfalsifiable claim? Back: A claim stated so that no possible observation could contradict it, so it asks for trust rather than evidence.

Front: Why is 'studies show' a red flag? Back: It hides the source, the sample, and the number, leaving nothing to verify.

Front: How do you handle a sentence mixing evaluation and fact? Back: Split it, then test only the checkable part, for example the battery claim under 'waste of money'.

Front: Can an opinion be supported by evidence? Back: Yes. Its value conclusion can rest on factual premises that are themselves testable.

Front: What is wrong with 'everyone in town loves it'? Back: It names no defined group or measure, so no result could confirm or refute it.

Front: What should a good rewrite of a vague claim include? Back: A number, a defined group or comparison, a measurement, and a time frame.

Front: Why are facts sometimes revised? Back: A fact is a claim with very strong evidence, and better evidence can overturn it.

What You Walk Away With

• Every statement you meet is a fact, an opinion, or a testable claim, and the label tells you what to do next.
• "What evidence would settle it?" is the whole method in one question.
• Vague claims and unfalsifiable claims cannot be checked, so they should not be believed, only parked.
• Mixed sentences are normal: split them, test the checkable part, and respect the value judgment for what it is.

Next up, we look at the tricks that make weak claims feel strong: Logical Fallacies in Everyday Arguments.