Topic 3 — Operating Decisions & the Income Statement (经营决策与损益表)
1. Operating Decisions & IS Link (经营决策与损益表的联系)
Definition / 定义: Operating decisions shape pricing/production/staffing/expense control and flow to the income statement as revenues and expenses（经营决策涵盖定价、生产、人力与费用控制，并通过收入与费用体现在损益表上）Example / 例子: Hiring five salespeople raises salary expense but may increase revenue（新增5名销售人员会增加薪资费用，但可能提升收入）Extension / 拓展: Sound decisions raise profitability and sustainability; poor ones add costs and cut income（合理决策提升盈利与可持续性；不当决策抬高成本并压低利润）
2. Operating Cycle (经营周期)
Definition / 定义: Purchase/manufacture → deliver goods/services → pay suppliers → collect from customers（采购/生产→交付→支付供应商→收款）Example / 例子: Retailer buys on credit, sells, then collects and later pays suppliers（零售商赊购、销售、收款后再付款）Extension / 拓展: Shorter cycles improve cash flow; longer cycles increase financing pressure（周期短改善现金流；周期长加大融资压力）
3. Time Period Assumption (会计期间假设)
Definition / 定义: Report for short artificial periods (monthly/quarterly/annually) despite a long-lived business（尽管企业持续经营，也需按月/季/年等短期报告）Example / 例子: Service on Dec 31 belongs to current year even if cash is received in January（12月31日完成的服务应计入当年，即便1月收款）Extension / 拓展: Requires cutoff/allocations and end-period estimates (depreciation, accruals)（需要截止与分摊及期末估计，如折旧与应计）
4. Elements on the Income Statement (损益表要素)
Definition / 定义: Revenues/Expenses from ongoing operations; Gains/Losses from peripheral activities（收入/费用来自持续经营；收益/损失多为非主营）Example / 例子: Pizza sales & wages vs. gain on sale of land（披萨销售与工资 vs. 出售土地收益）Extension / 拓展: Separating operating vs. non-operating clarifies core profitability（区分经常性与非经常性有助于评估核心盈利）
Definition / 定义: Net Income = Revenues − Expenses + Gains − Losses（净利润=收入−费用+收益−损失）Example / 例子: Operating income 17,800 + investment income 1,000 + gain 3,000 → NI 21,800（营业利润17,800+投资收益1,000+处置收益3,000→净利21,800）Extension / 拓展: NI links to Retained Earnings in equity（净利润结转至股东权益中的留存收益）
6. Cash Basis vs. Accrual Basis (现金基础 vs 权责发生制)
Definition / 定义: Cash basis records on cash receipt/payment; accrual basis records when earned/incurred（现金基础按收付现确认；权责发生制按实现/发生确认）Example / 例子: Dec 31 delivery, Jan 5 cash → cash basis Jan revenue; accrual basis Dec revenue（12/31交付、1/5收现→现金基础记1月；权责发生制记12月）Extension / 拓展: GAAP/IFRS require accrual for faithful performance measurement（GAAP/IFRS要求权责发生制以真实反映绩效）
7. Accrual Accounting (权责发生制)
Definition / 定义: Recognize assets/liabilities/revenues/expenses when transactions occur, not when cash moves（在交易发生时确认资产/负债/收入/费用，而非现金收付时）Example / 例子: Accrue year-end wages: Dr Wages Expense; Cr Wages Payable（年末计提工资：借工资费用；贷应付工资）Extension / 拓展: Implemented via adjusting entries (accruals/deferrals) to place items in proper periods（通过应计与递延调整把项目放入正确期间）
8. Revenue Recognition Principle (收入确认原则)
Definition / 定义: Recognize revenue when earned and realized/realizable—typically at delivery/transfer of control（在收入被赚取且已实现/可实现时确认，通常在交付或控制权转移时）Example / 例子: Credit sale at delivery: Dr A/R; Cr Sales Revenue（赊销在交付时确认：借应收账款；贷销售收入）Extension / 拓展: Upfront cash → Unearned Revenue (liability) until performance occurs（先收款→在履约前记预收收入〔负债〕）
9. Matching & Expense Recognition (配比与费用确认)
Definition / 定义: Recognize expenses in the same period as related revenues（费用与其相关收入在同一期间确认）Example / 例子: COGS recorded when related goods are sold, not when inventory was purchased（销售商品时确认销售成本而非采购时）Extension / 拓展: Use accruals (e.g., wages payable) and deferrals (e.g., prepaid rent) to implement matching（通过应计与递延实现配比）
10. Measurement in Operations (经营活动的计量)
Definition / 定义: Historical cost vs. fair value; LCM to avoid overstatement（历史成本与公允价值；采用成本与市价孰低防止高估）Example / 例子: Inventory recorded at $10,000 though market is $12,000（市价12,000也按成本10,000入账）Extension / 拓展: Historical cost is objective/stable; fair value is relevant/volatile（历史成本客观稳定；公允价值相关但波动大）
11. T-Accounts & Debit/Credit Rules (T账户与借贷规则)
Definition / 定义: Assets/Expenses: Debit↑ Credit↓; Liabilities/Equity/Revenues: Debit↓ Credit↑（资产/费用：借增贷减；负债/权益/收入：借减贷增）Example / 例子: Buy equipment for cash: Dr Equipment; Cr Cash（现金购置设备：借设备；贷现金）Extension / 拓展: Normal balances help detect posting errors（正常余额有助于发现过账错误）
12. Accounting Equation & Retained Earnings (会计等式与留存收益)
Definition / 定义: Assets = Liabilities + Stockholders’ Equity; RE = Beg RE + NI − Dividends（资产=负债+权益；留存收益=期初+净利−股利）Example / 例子: Beg RE 30,000; NI 10,000; Div 2,000 → End RE 38,000（期初30,000、净利10,000、股利2,000→期末38,000）Extension / 拓展: Revenues (credit) raise RE; expenses (debit) reduce RE; dividends reduce RE（收入贷记增RE；费用借记减RE；股利减少RE）
13. Adjusting Entries—Purpose & Types (调整分录：目的与类型)
Definition / 定义: Ensure period-end statements are accurate; apply accrual & matching（保证期末报表准确，落实权责发生与配比）Example / 例子: Types: accrued revenues/expenses, prepaid allocations, unearned revenue releases, depreciation, error fixes（类型：应计收/费、预付分摊、预收转收入、折旧、差错更正）Extension / 拓展: Each adjustment affects both IS and BS (income & a related asset/liability/equity)（每笔调整同时影响损益表与资产负债表）
14. Accrued Revenues (应计收入)
Definition / 定义: Earned but not yet billed/received; record receivable and revenue（已赚取但未开票/未收款；确认应收与收入）Example / 例子: Dr Interest Receivable; Cr Interest Revenue（借利息应收；贷利息收入）Extension / 拓展: Cash collection later: Dr Cash; Cr Receivable (no new revenue)（之后收现仅冲减应收，不再确认收入）
15. Accrued Expenses (应计费用)
Definition / 定义: Incurred but unpaid; record expense and payable（费用已发生但未支付；确认费用与应付）Example / 例子: Dr Wages Expense; Cr Wages Payable（借工资费用；贷应付工资）Extension / 拓展: Later payment: Dr Payable; Cr Cash; no current-period expense impact（付款时借应付贷现金；不再影响本期费用）
16. Prepaid Expenses (预付费用)
Definition / 定义: Cash paid upfront → asset; expense recognized as benefits are consumed（先付现金形成资产；随受益消耗转为费用）Example / 例子: Monthly amortize prepaid insurance: Dr Insurance Expense; Cr Prepaid Insurance（每月摊销预付保险：借保险费；贷预付保险）Extension / 拓展: Prevents overstating assets and understating expenses（避免资产高估与费用低估）
17. Unearned Revenues (预收收入)
Definition / 定义: Cash received before performance → liability; recognize revenue as delivered（先收款未履约记负债；履约时转收入）Example / 例子: Dr Unearned Revenue; Cr Revenue (monthly portion)（按期借预收收入；贷收入）Extension / 拓展: Disclose as current liability if recognized within a year（一年内确认的预收列为流动负债）
18. Depreciation & Accumulated Depreciation (折旧与累计折旧)
Definition / 定义: Allocate tangible asset cost over useful life; use a contra-asset to offset book value（将有形资产成本在寿命内分摊；用抵减资产反映净值）Example / 例子: Dr Depreciation Expense; Cr Accumulated Depreciation（借折旧费用；贷累计折旧）Extension / 拓展: Depreciation is allocation, not cash outflow or valuation change（折旧是分摊，非现金流出或公允价值变动）
19. Sales & COGS (销售与销售成本)
Definition / 定义: Merchandise sale needs two entries: record revenue/cash (or A/R) and move cost from inventory to COGS（商品销售需两条分录：收入与现金/应收；存货转销售成本）Example / 例子: Dr Cash; Cr Sales Revenue; Dr COGS; Cr Inventory（借现金；贷销售收入；借销售成本；贷存货）Extension / 拓展: Under perpetual systems, cost entry occurs at each sale; periodic records at period-end（永续盘存逐笔结转；定期盘存期末统一结转）
20. Credit Sales & Collections (赊销与收款)
Definition / 定义: Delivery creates A/R and revenue; later cash collection reduces A/R, not new revenue（交付时形成应收与收入；后续收现仅减少应收，不产生新收入）Example / 例子: Sale: Dr A/R; Cr Sales Revenue → Collection: Dr Cash; Cr A/R（销售：借应收；贷收入→收款：借现金；贷应收）Extension / 拓展: Monitor collectability; consider allowance for doubtful accounts（需监控回收风险并计提坏账准备）
21. Trial Balance & Posting (试算表与过账)
Definition / 定义: Post T-account balances into a (post-adjustment) trial balance to verify Debits = Credits（将各T账户期末余额汇总成〔调整后〕试算表以核对借贷相等）Example / 例子: Debits 760 = Credits 760 before statement preparation（出报表前借贷均为760）Extension / 拓展: Use as the working schedule to prepare IS, RE statement, and BS（作为编制利润表、留存收益表与资产负债表的底稿）
22. Closing Entries (结账分录)
Definition / 定义: Reset temporary accounts (revenues/expenses) to zero and transfer NI to RE（将临时科目清零并把净利润结转至留存收益）Example / 例子: Debit all revenues; credit all expenses; plug to Retained Earnings（借记所有收入、贷记所有费用，差额转入留存收益）Extension / 拓展: Post-closing trial balance keeps only permanent accounts for next period（结账后试算表仅保留永久性账户，作为下期期初）
23. Dividends (股息)
Definition / 定义: On declaration: Dr Retained Earnings; Cr Dividends Payable; on payment: Dr Dividends Payable; Cr Cash（宣告时借留存收益贷应付股息；支付时借应付股息贷现金）Example / 例子: Declare & pay 10,000 reduces RE and cash but not NI（宣告并支付10,000减少留存收益与现金，不影响净利润）Extension / 拓展: Dividends are distributions, not expenses—bypass the income statement（股息属利润分配，非费用，不通过损益表）
24. Financial Statement Flow (报表勾稽关系)
Definition / 定义: IS yields NI → updates RE statement → flows into BS equity; CFS explains cash change（利润表产出净利→更新留存收益→进入资产负债表权益；现金流量表解释现金变动）Example / 例子: Revenue 210, Expenses 135 → NI 75 → Ending RE increases by 75（收入210、费用135→净利75→期末留存收益+75）Extension / 拓展: End-of-period cash on CFS ties to cash on BS（现金流量表的期末现金与资产负债表现金相等勾稽）