## Joint Products, By-Products, and Co-Products
### Definitions
Joint Products (JP): Two or more products of almost equal value, produced simultaneously from the same raw material in the same process, in natural proportions that management cannot alter.
- Example: Oil refining produces kerosene, petrol, and diesel simultaneously.
By-Products (BP): Products of relatively small value that emerge incidentally while manufacturing the main product.
- Example: Rice milling — Rice is the main product; Husk is the by-product.
Co-Products (CP): Two or more products that are NOT necessarily of equal value, NOT necessarily produced from the same raw material, NOT necessarily in the same process, and whose proportions can be changed by management.
- Example: Wheat and other grains grown on separate farms through separate cultivation.
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### Key Distinctions
| Feature | Joint Products | By-Products |
|---|---|---|
| Value | Almost equal | Relatively small |
| Production | Simultaneous | Incidental (alongside main product) |
| Feature | Joint Products | Co-Products |
|---|---|---|
| Proportions | Fixed by nature (cannot be changed) | Can be changed by management |
| Raw material | Same for all | Not necessarily same |
| Process | Same process | Not necessarily same process |
| Value | Almost equal | Not necessarily equal |
> Management choice: Management is free to classify all outputs as joint products OR treat one as the main product and the rest as by-products.
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### Methods of Apportioning Joint Costs
The split-off point is where individual products become separately identifiable from the joint process.
| Method | Basis | When Suitable / Limitations |
|---|---|---|
| Physical Unit Method | Physical volume (kg, litres, etc.) at split-off | Not suitable when cost has no relation to physical volume |
| Average Unit Cost Method | Total Joint Costs ÷ Total units of all JPs | Not suitable when JPs have different units of measurement (e.g., one in kg, other in litres) |
| Survey / Points Value Method | Points assigned based on relative importance via technical survey | Considers all production and distribution factors |
| Contribution Margin Method | Variable costs → physical volume; Fixed costs → contribution margin ratio | When joint costs can be split into fixed and variable |
| Market Value at Separation Point | Market value of each JP at the split-off point | When all JPs are NOT subject to further processing, OR when further processing costs are disproportionate |
| Market Value after Further Processing | Market value of each JP after further processing | When all JPs ARE subject to further processing, OR when further processing costs are disproportionate |
| Net Realisable Value (NRV) Method | NRV = Sales value after further processing − Further processing costs | When all JPs are subject to further processing, OR costs are disproportionate |
Formula — Contribution Margin Ratio:
$$\text{CMR} = \frac{\text{Contribution of individual product}}{\text{Total contribution of all products}} \times 100$$
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### Treatment of By-Product Costs
| Case | Situation | Treatment |
|---|---|---|
| Case 1 | BP has small value | Do NOT apportion joint costs to BP. Credit sale value of BP to Costing P&L A/c OR to the Process A/c in which BP arose. |
| Case 2 | BP has considerable value | Apportion joint costs to BP using any of the 7 methods. Credit sale value to BP A/c; transfer BP A/c's P&L to Costing P&L A/c. |
| Case 3 | BP requires further processing | Apply Case 1 or Case 2 treatment depending on whether BP has small or considerable value. |
| Case 4 | BP is used internally by the undertaking | Debit replacement price (market price) of BP to the Process A/c where BP arose; credit replacement price to BP A/c. |