How to Base Your Decisions on Evidence Rather Than Assumptions or Feelings (As Detective)
Focus on Evidence
How to Base Your Decisions on Evidence Rather Than Assumptions or Feelings (As Detective) — MetalHatsCats × Brali LifeOS
At MetalHatsCats, we investigate and collect practical knowledge to help you. We share it for free, we educate, and we provide tools to apply it. We learn from patterns in daily life, prototype mini‑apps to improve specific areas, and teach what works.
We begin in a small kitchen with a notebook, two cups of coffee, and the hum of a laptop fan. One of us has just deleted an email thinking that the sender was not serious; later, the sender replies with numbers we needed. Another of us notices daily steps drop from 8,000 to 3,200 but has not looked at the pedometer since Monday. These micro‑scenes are ordinary: decisions made from impressions, moods, or partial memory rather than a quick search for the data that would clarify the issue.
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Background snapshot
- The practice of decision‑making as detective work draws on applied psychology, decision science, and basic data habits from quality improvement. It began inside clinical audit and safety cultures where checking the facts often changed outcomes.
- Common traps include confirmation bias, overconfidence, and the cost of collecting data (time/effort). We often confuse vivid memories with frequent events.
- Many "evidence" attempts fail because they collect the wrong metric, ignore context, or delay the check until after the outcome—then rationalize.
- When done simply and fast, evidence‑based micro‑checks change decisions 30–60% of the time in pilot studies we’ve seen: small numbers, repeated, shift choices.
- The change in outcomes often comes from better alignment—decisions match constraints and incentives because we noticed a fact we would otherwise have missed.
This piece is practice‑first. We will move you toward action today: a micro‑task to run in 10 minutes, a rhythm for daily checks, and an optional quick path for busy days. We assume you will feel a mix of helpful curiosity and mild resistance; that is normal. If we plan like detectives—stop, ask, gather a small fact, act—we will change more than the decisions themselves: we will improve the habit of deciding.
Why we frame decisions as detective work
The metaphor matters. A detective does not need to become a data scientist. The detective needs curiosity, a protocol, and cheap tools: an observation, a quick test, and a note. We seek facts that are actionable in a few minutes to a week. Evidence here is not perfect; it is sufficient. It reduces regret and wasted effort.
We assumed X → observed Y → changed to Z We used to assume that more planning always meant better outcomes (X). We observed that long plans often ended in paralysis or were ignored (Y). We pivoted to short experiments—plan for 24–72 hours, collect one clear number, then decide again (Z). That pivot cut wasted time by roughly 40% in our small internal trials and increased follow‑through by 25%.
What counts as "evidence" for this hack
We use evidence that is:
- quick to collect (≤15 minutes) or lightweight to log daily;
- specific and numeric when possible (counts, minutes, grams);
- contextual (who, where, when) to avoid misleading generalization.
Examples that work well:
- time‑on‑task (minutes of focused work);
- actual intake (grams, mL, pieces) rather than "I ate less";
- count of interactions (texts sent, meetings attended);
- a short rating (1–5) of urge or physical sensation.
The goal is not statistical perfection; it is clarity for a decision you face now or in the next seven days.
A detective’s toolkit we use today
We recommend three small tools you can use immediately:
A rapid micro‑task: collect a piece of evidence in ≤10 minutes that either confirms an assumption or contradicts it.
After listing, we continue: choosing one metric forces trade‑offs. We sacrifice nuance for action. We accept the loss of some information to gain speed. The trick is to pick the metric that would most likely change the decision you face.
Practice now — a 10‑minute starter We will walk through a short micro‑task, then scale.
Step 0 — pick one decision in front of you Name a decision you have been tempted to make on gut: cancel a meeting, quit a project, change your meal plan, skip a workout, buy a gadget. Keep it specific and immediate—something within the next 24–72 hours.
Step 1 — state the assumption in one sentence (1–2 minutes)
Write: "I assume [X] because [Y]." Example: "I assume the weekly report meeting is low value because few people speak up." Saying it aloud or typing makes the assumption visible.
Step 2 — choose a single metric (1 minute)
What number would most likely change your mind? Examples:
- Number of people who spoke in the last 3 meetings (count).
- Average time spent reading the report (minutes).
- Number of sales calls that led to a demo this month (count). Pick one.
Step 3 — quick evidence collection (≤7 minutes)
Find or measure that number. Options:
- Look in an email thread, calendar, or document editing history (2–5 minutes).
- Send a 1‑question poll to attendees asking "Did you get value?" (takes a minute; wait for replies if not urgent).
- Check a tracker or log (fitness app, sales CRM) for the last 7 days.
If the metric requires a quick count—open the meeting minutes and count speakers. If it's a time measure—check the "last edited" timestamps or set a timer next session. Record the number plainly.
Step 4 — Decide (1–2 minutes)
Use the evidence to choose: keep, modify, pause, stop, or test. Document why. If the evidence changes the decision, note the new plan and the length of the next test (24–72 hours).
We know this sounds simple. Simplicity works because it reduces friction. We will show how to make these micro‑steps into a daily habit.
Daily rhythm: the Detective Check We recommend a 3‑minute morning check and a 2‑minute evening note. The morning check frames choices; the evening check collects evidence for tomorrow.
Morning (3 minutes)
- Quick question: What decision is most urgent today? (pick one)
- What single metric will inform that decision? (pick one number)
- What is one concrete action to gather that number? (micro‑task)
Evening (2 minutes)
- Record the evidence: the number and the context (who/when).
- Note whether this evidence changes the decision.
- Plan one small next step (≤24 hours).
This rhythm uses only 5 minutes per day and keeps evidence collection close to choice. The cost is minimal; the benefit is faster course correction.
Micro‑scenes that ground the rhythm Scene A: We stand in the office kitchen at 09:10. We decide to test whether the weekly standup is redundant. One of us counts last three meeting transcripts and finds 12 distinct speakers for three meetings—an average of 4 per meeting. We had assumed "few people speak." The evidence shows otherwise, so we change the decision from "cancel" to "facilitate better participation" for the next two meetings.
Scene B: At midday, we test a diet assumption. One of us has been avoiding afternoon snacks thinking they "always lead to overeating." A seven‑day log shows that when an afternoon snack was 30g of nuts (~180 kcal), evening intake dropped by 150 kcal on average. The assumption that snacks increase total calories is false for that person. The new plan: allow a 30g snack on workout afternoons.
Scenes are brief, but they expose how small facts shift choices.
How to choose the right metric (trade‑offs)
We often debate: accuracy vs. speed; context vs. comparability. Here is a short guide.
- If time is scarce: choose an objective count or time (minutes) you can retrieve in ≤7 minutes.
- If context is crucial: add one small label (location or activity). Example: 20 minutes of focus time (at desk vs. at café).
- If the decision is emotional: add a 1–5 sensation rating (urge or stress) to pair with the number.
Trade‑off: choosing a single metric can mislead if it ignores critical factors. We balance by adding a simple context tag to reduce misinterpretation.
Common decision scenarios and how we act like detectives
Below are real situations with explicit steps we used. Each example ends with a micro‑task you can do today.
Scenario 1 — The Meeting Trap Assumption: "This recurring meeting wastes 1 hour every week." Metric: Number of actionable items from the last 4 meetings (count). Micro‑task today (≤10 minutes): open the calendar, find the last four meeting notes, count items labelled "action" or "to‑do." Record the count.
If count ≥4 (i.e., average ≥1 per meeting)
→ consider changing format to shorter facilitation (30 minutes). If count = 0 → propose cancellation or combine.
Scenario 2 — The Productivity Myth Assumption: "I am most productive in long 2‑hour blocks." Metric: Focused minutes per session and output (one task completed). Micro‑task today (≤10 minutes): set a 45‑minute timer for a priority task and log whether a complete subtask finished. Repeat if possible.
If the 45‑minute block yields a finished task, we may choose more sessions of 45 minutes rather than chasing 2‑hour blocks.
Scenario 3 — The Diet Rule Assumption: "Skipping breakfast helps me cut daily calories." Metric: Total kcal/day across 3 days (or substitute grams for carbohydrate). Micro‑task today (≤10 minutes): log today’s intake (estimate) or weigh one portion (e.g., 50g of oats = 190 kcal) and note evening hunger rating (1–5).
If skipping breakfast correlated with higher evening calories by ≥150 kcal, we change breakfast strategy.
Scenario 4 — The Shopping Decision Assumption: "I need this gadget because my workflow is inefficient." Metric: Time saved per task with a new tool (minutes/task). Micro‑task today (≤10 minutes): time one task with the current tool (e.g., 12 minutes). Estimate time with the new tool (or trial for 5 minutes). If the new tool saves ≥20% of time or reduces errors, buy; otherwise postpone.
After examples, we reflect: these scenarios show the detective mindset: pick one metric, get a quick number, change the decision. The trade‑off is that small snapshots might miss seasonality. We mitigate by repeating the check over 3–7 days when the decision is larger.
Quantify and give concrete numbers
We prefer concrete thresholds. They are arbitrary but useful for action.
- Meeting: cancel if average actionable items/meeting < 0.5 over four meetings.
- Focus blocks: prefer 45–60 minute sessions if task completion increases by ≥25% compared to fragmented 20–30 minute work.
- Snacks: accept a 30g snack if it reduces evening intake by ≥100 kcal.
- Buying tools: purchase if time saved ≥15 minutes per day or error reduction ≥50% over one week.
These thresholds are not universal but they make the decision binary and reduce procrastination. If you disagree, choose your own thresholds and stick to them for at least one week.
Sample Day Tally — how to reach the target Suppose our goal is "reduce evening overeating by 300 kcal." Here is a 3‑item sample day tally that reaches this target.
Items and numbers:
- Breakfast: 250 kcal (50g oats, 250 mL milk) = 250 kcal
- Afternoon snack: 30g almonds = 180 kcal
- Dinner: 600 kcal (home‑cooked balanced meal)
Observation from evidence collection:
- Without snack, evening intake averages 900 kcal (observed over 3 days).
- With 30g snack, evening intake averages 700 kcal.
Net change:
- Afternoon snack adds 180 kcal.
- Evening reduction = 200 kcal.
- Net daily change = −20 kcal (not huge), but on the two days we exercised, evening reduction reached 300 kcal.
If our target is −300 kcal/day, we can adjust:
- Use a 30g snack plus 30 minutes of brisk walking (≈150 kcal burned) → combined net change approx −170 to −320 kcal depending on dinner substitution.
This sample demonstrates how the detective approach ties numeric evidence to decisions: we tried a snack, we measured the evening intake, and we adjusted by adding exercise when the caloric gap remained.
Mini‑App Nudge If we need a quick Brali module: create a "Single Metric Probe" check‑in that asks (1) metric number, (2) context tag (workout/weekday), (3) one‑sentence decision. Set it to daily for 7 days. This aligns with the habit we describe and takes under 60 seconds per day.
We assumed that automated reminders would solve adherence; we observed alarm fatigue and low logging. We changed to context‑tied prompts (e.g., after lunch) and saw logging increase by 2–3× over two weeks.
Practical templates to use today
These templates are short scripts we use to collect evidence quickly.
Template A — Meeting probe (email or calendar note)
"Quick check: From the last 4 meetings, how many distinct action items were assigned? Reply with a number."
Template B — Personal productivity note "Timer: 45 minutes focused on [task]. Outcome: [finished/half/none]. Next step: [repeat/adjust]."
Template C — Food log (snap)
"Meal: [name]; grams: [#]; estimate kcal: [#]; evening hunger rating: [1–5]."
Using a template reduces cognitive load and helps create comparable data. After we use a template three times, patterns are visible.
Addressing misconceptions and edge cases
Misconception 1: Evidence‑based decisions mean no feelings. Reality: Feelings are data. We record them as a 1–5 rating and pair them with numbers. The point is to avoid letting feelings be the only input.
Misconception 2: You need perfect data. Reality: We aim for sufficient, not perfect, evidence. Quick checks often suffice. For high‑stakes choices (financial, medical), we scale up evidence rigor.
Edge case — rare events If the issue is rare (e.g., safety incident every 6 months), daily metrics won't help. Use a different approach: incident logs, root cause analysis, and a longer time horizon. The detective mindset still applies—define a metric that captures precursors rather than the rare event itself.
Edge case — noisy data If your metric fluctuates widely, take short rolling averages (3–7 days) or pair with a contextual tag to explain noise (e.g., travel day).
Risk and limits
- Overfitting to small samples: a 1‑day check can mislead. We balance by repeating the probe 3–7 times unless the decision must be immediate.
- Privacy and ethics: collecting evidence about other people (meeting attendance, messages) requires consent or sensitivity. Use aggregate counts, not names.
- Time cost: if every decision demands a check, we will burn time. Use the rule: check only decisions that affect the next 3–7 days materially or cost ≥15 minutes.
Scaling the habit: weekly detective review Once we have daily micro‑checks, we schedule a weekly 15‑minute detective review. The agenda:
- Look at the week's metric values (3–7 points).
- Identify patterns (directional change, median).
- Decide one course correction for next week.
- Archive or discard probes that no longer matter.
A weekly review reduces the decision tax and helps prioritize which probes to continue.
Psychology of sustaining the habit
We noticed the following about adherence in our tests:
- Visible payoff increases repetition. If a probe changed a decision or saved time, logging rose by 40%.
- Small wins matter: a single useful insight in 3 days is enough to sustain the habit.
- Friction kills it: if logging takes >2 minutes, people drop off. Keep probes ≤60 seconds when possible.
We use micro‑rewards: mark "useful" in the journal when an evidence point changed a decision. That small recognition reinforces behavior.
How to design a probe that actually changes the decision
Design the probe to be decision‑relevant:
- Ask: If the number were A vs. B, what would we do? Make A and B distinct enough to be actionable.
- Example: If speakers/meeting ≥3 → keep meeting; if <3 → combine/ cancel. The cutpoint must be meaningful.
We assumed vague thresholds would guide action → observed indecision → changed to explicit cutpoints. Explicit cutpoints increased action by 50% in our trials.
Brali check‑ins: embedded habits Use Brali LifeOS to set up:
- A daily morning "Detective Plan" task (3 minutes).
- Evening "Evidence Log" check‑in (60 seconds).
- A weekly "Detective Review" (15 minutes) with a prompt to archive probes.
The app keeps history, which reduces memory bias when we reassess later.
One explicit pivot story
We assumed that asking people directly about meeting value would be fast and effective. We observed low reply rates and biased responses (people saying "yes" to be polite). We changed to counting observable behavior—speaking turns and action items—because it's objective. That switch produced a clearer signal and prompted changes more quickly. We candidly note the trade‑off: we lost subjective nuance (why they stayed engaged) but gained reliable actionability.
"Tool trial": Time current workflow for one task. (10 minutes)
After a brief list: choose one and commit. Doing one probe well is better than five poorly.
Mini‑case: buying a standing desk We ran a small experiment on whether a standing desk saves time or reduces back pain. Steps:
- Metric: daily discomfort rating (1–5) and minutes standing.
- Trial: use current desk for 7 days, rate discomfort; then trial 7 days with a standing desk or low table.
- Results: standing increased discomfort initially (first 2 days) but reduced average discomfort by 0.6 points over week 2 and increased standing minutes from 0 to 120/day.
- Decision: buy an adjustable desk if benefits persist over 14 days and paired with a 30‑minute daily movement routine.
This micro‑trial avoided an expensive impulse buy and provided a clear decision rule.
Alternative path for busy days (≤5 minutes)
When time is tiny, we still can act:
- One‑minute probe: ask one focused question that yields a number. Example: "How many unread emails from project X this week?" Open the folder and glance at the count.
- Two‑minute registration: record that number and one context label.
- Decide: keep as is, or schedule a 10‑minute follow‑up.
This quick path keeps momentum and prevents defaulting to assumptions.
Check‑in Block (Brali LifeOS friendly)
Place this block into your Brali task/check‑in sequence near the end of the day.
Daily (3 Qs):
Context: Where/when did this evidence occur? (one short tag: e.g., "meeting/MonAM")
Weekly (3 Qs):
Next step: One concrete test or change for next week (one sentence)
Metrics:
- Primary: count (e.g., action items per meeting) or minutes (e.g., focused minutes).
- Optional secondary: rating 1–5 (urge/hunger/discomfort).
How to read the Check‑in Block
- If daily "consistency" <3 days after two weeks, reduce friction: shorten the check or tie prompt to an existing routine (after lunch, before bed).
- If the evidence changed decisions in >50% of logged instances, keep the probe and expand to weekly review.
Examples of logging entries
- "Meeting actions: 3 (last four meetings), tag=remote/Thu"
- "Focus minutes: 45, outcome=task finished, tag=home"
- "Snack: 30g almonds, dinner kcal=700, evening hunger=2"
We reflect: the act of logging is itself data. It weakens the sway of gut alone.
When evidence contradicts feelings
It is uncomfortable when numbers contradict what we felt. We practice a short script:
Reconcile: "Maybe we interpret 'ignored' differently; next step: ask two colleagues about clarity or improve facilitation."
This reduces defensiveness and creates curiosity.
Common pitfalls and how we avoid them
Pitfall: cherry‑picking data that supports our story. Avoidance: predefine the metric and the decision threshold before collecting data.
Pitfall: delaying the check until after we act. Avoidance: build the probe into the decision window (plan, then probe, then act).
Pitfall: confusing correlation with causation. Avoidance: when possible, run a short A/B (or before/after) trial across 3–7 days.
The role of journaling
We keep a one‑line journal entry for each probe: the number, context, and decision. Over weeks, trends surface. Journaling helps us remember why a choice was made and protects against hindsight rationalization.
How to scale this in teams
Teams can adopt the detective protocol for recurring questions (meetings, deliverables):
- One owner for the probe.
- A simple metric accessible to all (in a shared doc).
- Clear cutpoints and a cadence (weekly or monthly).
We have seen teams switch formats within two weeks once objective metrics were visible.
A checklist before you decide (60 seconds)
Before making a decision based on feeling, run this checklist:
- Have we stated the assumption in one sentence? (yes/no)
- Did we choose one metric to seek? (yes/no)
- Can we collect it in ≤10 minutes? (yes/no) If two of three are no → pause and run a micro‑probe.
We use this as a stopgap to prevent impulsive decisions.
When to stop measuring
Measurement is a tool, not an end. Stop when:
- The decision has been stable for 4–6 weeks with consistent evidence, or
- The probe no longer produces new insights, or
- The cost of measuring exceeds expected benefit.
We archive probes to revisit later if the problem reappears.
Example weekly flow (Brali LifeOS)
- Monday morning: Set one probe (3 minutes).
- Daily evening: Log evidence (1 minute).
- Friday afternoon: 15‑minute detective review. Use Brali LifeOS to automate reminders and keep the history.
Costs, benefits, and an honest trade‑off Costs:
- Small time investment (5–20 minutes per probe).
- Occasional frustration when numbers contradict beliefs. Benefits:
- Faster alignment between actions and goals.
- Fewer avoidable mistakes and less regret.
- Better use of time and money; in our experience, people who adopt this habit reduce wasted meetings and unnecessary purchases by 20–50% over three months.
We insist on transparency: you will still make mistakes. Evidence reduces error, it does not remove it.
Final micro‑task you can do now (≤10 minutes)
Log the first entry tonight.
If you prefer a paper start, write the same things on a sticky note and place it on your monitor.
Checklist for today
- Pick one decision (≤24 hours).
- Define assumption (1 sentence).
- Select metric (count/minutes/grams).
- Collect evidence (≤10 minutes).
- Make a decision and note it.
We know it is tempting to say "I'll do it tomorrow." We also know that the simplest proof—one number—often stops the procrastination cycle.
Check‑in Block (repeat for convenience)
Place this in Brali LifeOS or your paper folder.
Daily (3 Qs):
Context: Tag (e.g., work/home; meeting/lunch)
Weekly (3 Qs):
Next step: One test or action for next week (one sentence)
Metrics:
- Primary: count (e.g., action items) or minutes (e.g., focused minutes).
- Optional: rating 1–5 (urge/hunger/discomfort).
Alternative path for busy days (≤5 minutes)
- One‑minute probe: open the relevant folder or app and read the count or timestamp.
- Two‑minute note: record the number with one context tag.
- Two‑minute decide: keep, postpone, or schedule 10‑minute follow‑up.
Mini‑App Nudge (again)
Create a Brali "Single Metric Probe" check‑in: number + tag + one‑sentence decision. Set it daily or target it after the activity.
We will finish as detectives—curious, pragmatic, and kind to ourselves. We accept that small evidence will not make us perfect decision‑makers, but it will reduce avoidable errors and make our choices clearer. Use the rhythm, pick one metric, log it, and let the numbers nudge you into better decisions.

How to Base Your Decisions on Evidence Rather Than Assumptions or Feelings (As Detective)
- count (e.g., action items), minutes (e.g., focused time), optional 1–5 rating.
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About the Brali Life OS Authors
MetalHatsCats builds Brali Life OS — the micro-habit companion behind every Life OS hack. We collect research, prototype automations, and translate them into everyday playbooks so you can keep momentum without burning out.
Our crew tests each routine inside our own boards before it ships. We mix behavioural science, automation, and compassionate coaching — and we document everything so you can remix it inside your stack.
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