Authoritative Constraint File #2

Authoritative Constraint File - add this to the folder too.


File Name: 02_Assumptions_Log.md


File Authority

This is an authoritative constraint file.
Its contents govern how conclusions may be interpreted and revised.

Any conclusion that relies on an unlogged assumption is invalid until that assumption is documented here.

Purpose of This File

This file exists to make assumptions visible before they become conclusions. It records assumptions as they are identified, evaluates their validity, and tracks whether they are accepted, revised, or rejected.

Assumptions are treated as provisional by default. Acceptance requires explicit justification.

Assumption Log

Assumption A1

Statement:
A newer vehicle will be more reliable than an older used vehicle.

Source of Assumption:
Common consumer belief; initial user intuition.

Status:
Challenged

Reasoning / Evidence:
Preliminary review of reliability reports suggests that some older models with proven track records outperform newer models with redesigned components. Age alone is an insufficient proxy for reliability.

Impact if False:
High. This assumption strongly biases the decision toward newer vehicles and higher cost.

Disposition:
Rejected as a general rule. Reliability must be evaluated model-by-model using sourced data.

Assumption A2

Statement:
Higher purchase price implies higher build quality and durability.

Source of Assumption:
Implicit market signaling; brand positioning.

Status:
Challenged

Reasoning / Evidence:
Price reflects multiple factors including branding, features, and market positioning. Reliability data does not consistently correlate with purchase price.

Impact if False:
Medium to high. Could distort cost–benefit analysis.

Disposition:
Rejected. Price may correlate with features, not durability.

Assumption A3

Statement:
Vehicles with high online ratings are safer choices.

Source of Assumption:
Consumer review platforms.

Status:
Partially Accepted (with constraints)

Reasoning / Evidence:
Ratings often reflect early ownership satisfaction and subjective experience. They may not capture long-term reliability or ownership costs.

Impact if False:
Medium.

Disposition:
Accepted only as a weak signal. Ratings may inform but must not drive conclusions.

Assumption A4

Statement:
Maintenance costs for used vehicles will be significantly higher than for new vehicles.

Source of Assumption:
General ownership narratives.

Status:
Unresolved

Reasoning / Evidence:
Maintenance cost varies widely by model, prior usage, and service history. Insufficient data at this stage.

Impact if False:
High.

Disposition:
Deferred. Requires model-specific maintenance data before acceptance or rejection.

Assumption A5

Statement:
Predicting resale value is necessary to make a sound purchase decision.

Source of Assumption:
Common purchase advice.

Status:
Rejected

Reasoning / Evidence:
Resale value is influenced by market conditions and usage patterns beyond control. Given the five-year ownership horizon, resale uncertainty outweighs predictive value.

Impact if False:
Low to medium.

Disposition:
Excluded from decision criteria. Broad historical norms may be noted but not optimized for.

Assumption A6

Statement:
Financing terms materially affect the decision.

Source of Assumption:
Standard purchasing frameworks.

Status:
Out of Scope

Reasoning / Evidence:
This project explicitly excludes financing unless introduced later.

Impact if False:
Low under current constraints.

Disposition:
Deferred unless scope changes.

Assumption Review Summary

No conclusions may be treated as high confidence until unresolved assumptions with high impact are addressed.

Closing Note

Assumptions are not errors.
Unexamined assumptions are.

This file exists to ensure that conclusions rest on evidence and choice—not habit or intuition.