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A study note is a compressed record of a definition, method or rule. Compression becomes risky when its source edition, scope and example assumptions disappear. Two apparently conflicting notes may describe different periods, conventions or document statuses.
Keep identity separate from the access date
Record the source title and edition or dataset release. The date you opened a webpage is useful, but it does not define the underlying document version. A current page may host an older factor file, and a new announcement can describe a future standard rather than a present replacement.
| Source title and version | The actual method or dataset used |
| Covered period | Dates of the example or activity |
| Access date | When the source was inspected |
| Status | Published guidance, proposal or another state |
| Assumptions | Conditions making the calculation applicable |
The EPA factor-page example illustrates the distinction: a January 2026 webpage update did not establish a factor file titled 2026. Read the actual listed file and relevant row coverage before transferring it into a calculation.
Preserve the question next to the formula
A formula without its quantity definition can migrate into the wrong task. A rate per quarter and a nominal annual quotation are different representations. Gross future present value and already net project NPV are different amounts. A denominator measured in millions and one measured in base currency are different scales.
Keep the question and units beside the relationship. The calculator-state log and emissions comparison sheet give concrete examples of records that retain those definitions.
Make a correction traceable
Do not erase a wrong example so completely that you lose the reason it failed. Keep the original claim, the independent calculation and the corrected conclusion. This makes the next review about a concept rather than an unexplained replacement number.
| Original claim | A rate was reported as an IRR |
| Independent check | Substitute that rate into the stated NPV equation |
| Finding | NPV does not equal zero |
| Correction | Solve the root from the actual schedule |
| Scope | The ranking story must also be rechecked |
The reported-IRR audit shows why correcting one number can change the explanation of a comparison.
Separate current material from a proposal
A proposed reporting condition belongs in a proposal note. It should not silently replace a published method or become an inferred legal requirement. The GHG Protocol’s July 2026 timeline is an announced development plan; its future dates are not evidence that a consolidated replacement is already in force.
Review the set before a later practice session
Before using a note set again, inspect changed versions and unresolved assumptions. Keep a concise correction queue rather than rewriting every unchanged note. The aim is to know what supports the answer, not to produce a long provenance label on every line.
Read the calculator-diagnostic workflow for an example of retaining the failed state. Then use the model review log when your notes combine forecasts, constraints and computed results.
Frequently asked questions
Is an access date enough to identify a source version?
No. Record the actual edition, release or file identity as well as when it was accessed.
Should every note be rewritten when one example is wrong?
Keep unchanged material where appropriate, but trace the error and recheck any conclusion that depended on it. A corrected number can alter a ranking or explanation.
Sources
- EPA: Emission Factors Hub · epa.gov · Retrieved
- GHG Protocol: July 2026 standards-development FAQ · ghgprotocol.org · Retrieved
- CFA Institute: capital investments and allocation · cfainstitute.org · Retrieved
