This course has repeatedly flagged that the textbook model of monetary policy fits a developing economy loosely. This final module gathers those limits into one picture and adds the deepest one: fiscal dominance, where the central bank's independence is overwhelmed by the government's borrowing needs. Understanding these constraints is what separates a sophisticated reading of African monetary policy from a naive application of the textbook.
Fiscal dominance
Unpleasant monetarist arithmetic (Sargent-Wallace, 1981)
Monetary policy can control inflation only if it is not subordinated to the government's financing needs. Sargent and Wallace's 'unpleasant monetarist arithmetic' showed the limit: if the government runs persistent deficits and its debt is on an unsustainable path, then a central bank that tightens money today only delays inflation — because eventually the debt must be serviced, and if the market will not absorb more bonds, the central bank will be forced to print money to finance the government (monetise the deficit). In this regime — fiscal dominance — the fiscal authority, not the central bank, ultimately determines inflation. The central bank's independence becomes nominal: it can choose the timing of inflation but not its eventual level, which is set by the unsustainable fiscal path. Tight money today can even mean MORE inflation later (more debt to monetise). This is the most important limit on monetary policy in any country with weak fiscal discipline — and it connects directly to the deficit-bias and sovereign-debt material of the other courses.
How fiscal dominance shows up
- Direct central-bank financing — the bank lends to or overdraws for the government (sometimes beyond legal limits), directly expanding the money supply to cover deficits.
- Pressure to keep rates low — to reduce the government's debt-service burden, regardless of the inflation outlook (the political pressure of module 1, but structural).
- A captive banking system — banks pressured or required to hold government debt, crowding out private credit and tying the financial system to the sovereign (the bank-sovereign nexus).
- Independence on paper, not in practice — the de jure/de facto gap of the Governance course: a legally independent central bank that cannot in reality resist financing the government.
Shallow markets and dollarisation
Beyond fiscal dominance, two structural features (met throughout this course) cap monetary potency. Shallow, segmented financial markets break the transmission mechanism and the operating framework (modules 2–3), so the policy rate reaches the economy weakly and unpredictably. Partial dollarisation — where a significant share of deposits, loans, and pricing is in a foreign currency — directly limits monetary control: the central bank's domestic-currency tools do not reach the dollarised part of the economy, monetary policy loses traction, and the exchange-rate channel and balance-sheet risks dominate. A heavily dollarised economy has, in effect, partly outsourced its monetary policy to the country whose currency it uses.
The supply-shock and credibility limits
Two further limits round out the picture. Supply-shock dominance (module 5): when food and fuel drive inflation, monetary policy can do little about the first-round effect, so it is structurally less able to control the inflation people actually experience. And credibility deficits: a central bank still building its track record cannot anchor expectations as firmly as an established one, so shocks are more likely to spiral and the bank must work harder for less. Each of these — fiscal dominance, shallow markets, dollarisation, supply shocks, weak credibility — independently reduces the power of monetary policy; together they mean a developing-economy central bank operates with a weaker, less reliable lever than the textbook assumes, and must be judged accordingly.
The realistic verdict
The honest synthesis of the course: monetary policy in a developing economy is real but constrained — less potent, less predictable, and more dependent on fiscal discipline and structural reform than the textbook implies. This is not a counsel of despair; central banks across Africa have built credibility, brought down inflation, and managed crises. But it means the central bank cannot be the whole answer to macroeconomic stability, that fiscal discipline (the public-choice and budgeting courses) and financial-market development are preconditions for monetary policy to work well, and that a sophisticated observer judges an African central bank against its real constraints — not against a textbook written for deep markets, fiscal discipline, and hard-won credibility it may not yet have. Reading the constraints correctly is the whole point of the course.
Exercise
A central bank has a legal mandate for price stability and instrument independence, yet inflation stays stubbornly high. Investigation reveals: the government runs large, persistent deficits; the central bank has been providing 'advances' to the Treasury above its statutory limit; banks are heavily loaded with government securities; and the policy rate has been kept below inflation. (1) Diagnose the regime and name the concept. (2) Explain, using unpleasant monetarist arithmetic, why the central bank's legal independence is not delivering low inflation. (3) Explain why simply 'hiking rates and tightening' will not durably fix the inflation. (4) State what would actually be required, and connect it to the other public-economics courses.