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Lesson details
- Estimated study time
- 105 min
Learning objectives (5)
Straight-line, units-of-production, and declining-balance schedules can all be calculated correctly and still answer the wrong fact pattern. Method selection starts with the supported service-consumption pattern, not the expense shape a manager prefers.
Hold the common inputs steady
Before comparing methods, align asset cost, residual value, in-service date, estimated life or productive capacity, unit of account, and reporting period. Then ask what each method represents:
| Method | Allocation driver | Typical control |
|---|---|---|
| Straight-line | Equal full periods | Depreciable amount ÷ useful life |
| Units of production | Measured activity | Rate per estimated unit × actual activity |
| Declining balance | Opening carrying amount | Do not cross the supported residual floor |
For $105,000 cost, $5,000 residual, and 5 years, straight-line is $20,000 per full year. With 50,000 estimated units, units-of-production is $2 per unit; a 14,000-unit year receives $28,000. A 40% double-declining rate applied to the $105,000 opening amount gives $42,000 in year one, subject across the schedule to the residual floor.
The residual control becomes concrete in Year 5. After four unadjusted double- declining charges, carrying amount is $13,608. Another 40% would allocate only $5,443.20 and leave $8,164.80 after the stated five-year life. Under a bounded schedule that completes allocation in 5 years, the final charge is limited or switched as the stated method convention requires so no more than $8,608 remains to be allocated and carrying amount ends at the $5,000 residual. State that convention; do not hide it in a final-year plug.
The schedules differ in timing, not total supported depreciable amount. None is a market-value forecast or replacement fund.
US GAAP: Significant components may be depreciated separately, but a company can use one supported unit of account for the asset.
IFRS: IAS 16 requires separate depreciation for each significant part of an asset.
Effect: Suppose a $100,000 building includes a $20,000 roof with a 10-year life, while the remaining $80,000 has a 40-year life. With no residual value, separate components produce $4,000 of first-year depreciation: $2,000 for the roof and $2,000 for the rest. One 40-year asset produces $2,500.
Put the readiness date before the fraction
Payment, delivery, installation, testing, acceptance, and readiness can occur on different dates. State why the asset is ready for intended use at the chosen date, then apply the supplied monthly, daily, or other book convention.
For the straight-line asset above, April 1 readiness and a calendar-month convention produce 9 months, or $15,000 first-year expense. A tax half-year or mid-quarter convention is not silently substituted. Disposal and held-for- sale dates also constrain the final allocation under their applicable routes.
Group and composite extension
A group pool ordinarily contains similar assets; a composite pool can contain dissimilar assets. Sum the supported annual depreciation for all pool members and divide by total pool cost to derive a pooled rate. A composite life can be derived from total depreciable amount divided by total annual depreciation.
Pooling changes schedule mechanics, not the need for subledger integrity. Additions, ordinary retirements, proceeds, and material unusual events remain traceable. Do not apply a pool's ordinary-retirement convention to an individually accounted asset merely to avoid a gain or loss.
Changes and errors
The existing estimate-revision lesson supplies the information-timeline model: new support for residual value or remaining life generally changes allocation prospectively in its bounded case. A justified method change and a correction of erroneous data are not casually relabeled as estimate changes. State what changed, when evidence became available, and which prior accounting was supportable.
Interpret method comparisons carefully
Earlier expense can lower near-term profit and carrying amount and raise later profit relative to straight-line, holding other facts constant. Asset turnover and margins can change mechanically. Those patterns do not prove conservative reporting, economic obsolescence, cash generation, or manipulation. Ask about capital intensity, maintenance, utilization, policy consistency, and remaining service evidence.
Exit check
Prepare full schedules under all three methods for one aligned asset, including a partial first year and residual-floor control. Then explain which operating evidence would support each pattern, how a group pool would change the unit of account, and whether a later useful-life revision, method change, or input error would follow the same reporting route.