flowchart LR
    A["Public IT budget requests<br/>have unclear, subjective<br/>economic justification"] --"Calculate the present value<br/>of social costs and benefits"--> B["B/C ratio, NPV —<br/>objective feasibility judgment"] --"Budget allocation,<br/>priority setting"--> C["Maximize public benefit,<br/>use public resources efficiently"]

    style A fill:#FFEBEE,stroke:#D32F2F,color:#000
    style B fill:#E3F2FD,stroke:#1976D2,color:#000
    style C fill:#E8F5E9,stroke:#388E3C,color:#000
  

    flowchart TD
    subgraph COST["Cost items (C)"]
        direction LR
        C1["Initial build cost<br/>HW/SW, development, consulting<br/>data migration, training"]
        C2["Operations & maintenance cost<br/>Labor, licensing<br/>system operations, security"]
        C3["Opportunity cost<br/>Forgone alternative investment<br/>administrative transition cost"]
    end

    subgraph BENEFIT["Benefit items (B)"]
        direction LR
        B1["Direct benefits<br/>Time saved on work<br/>workforce efficiency, cost savings"]
        B2["Indirect benefits<br/>Fewer errors, better quality<br/>effects from linkage with other agencies"]
        B3["Social benefits<br/>Public benefit, accessibility<br/>administrative transparency and trust"]
    end

    COST --> RATIO["B/C Ratio<br/>= PV(benefits) / PV(costs)<br/>≥ 1.0 → feasible"]
    BENEFIT --> RATIO

    style COST    fill:#FFEBEE,stroke:#D32F2F,color:#B71C1C
    style BENEFIT fill:#E8F5E9,stroke:#388E3C,color:#1B5E20
    style RATIO   fill:#1E3A5F,stroke:#1E3A5F,color:#fff
  

    flowchart LR
    S1["Define the project<br/>Confirm purpose, scope,<br/>timeline, target"]
    S2["Calculate costs<br/>All build, operations,<br/>opportunity costs"]
    S3["Identify/quantify benefits<br/>Convert direct, indirect,<br/>social benefits"]
    S4["Apply a discount rate<br/>Social discount rate<br/>convert to present value"]
    S5["Calculate metrics<br/>B/C ratio<br/>NPV, IRR, payback period"]
    S6["Judge feasibility<br/>B/C ≥ 1.0<br/>positive NPV"]

    S1 --> S2 --> S3 --> S4 --> S5 --> S6

    style S1 fill:#E3F2FD,stroke:#1976D2,color:#000
    style S2 fill:#FFEBEE,stroke:#D32F2F,color:#000
    style S3 fill:#E8F5E9,stroke:#388E3C,color:#000
    style S4 fill:#F3E5F5,stroke:#7B1FA2,color:#000
    style S5 fill:#FFF3E0,stroke:#F57C00,color:#000
    style S6 fill:#1E3A5F,stroke:#1E3A5F,color:#fff