Why Can Crossing an Income Threshold by One Dollar Cost You a Benefit?

Geoffrey Chen

When Numbers Start Making Decisions · Season One, “People on Either Side of a Threshold” · Article 10

1. Can one dollar separate two people?

Imagine two otherwise identical single Australian retirees. Both have reached Age Pension age, neither receives an income-support payment from Centrelink or the Department of Veterans’ Affairs, and both satisfy the residence and other eligibility conditions. The only difference is that under the income test for the Commonwealth Seniors Health Card, one has annual income of $101,104 and the other has $101,105.

As at August 2026, the annual limit for a single applicant is $101,105. The rule requires income to be less than the limit. A person at or above it does not pass. In this example, the first retiree may satisfy the test and the second does not. Services Australia: “Income test for a Commonwealth Seniors Health Card” Social Security Act 1991, section 1071

Their economic positions differ by one dollar, while their institutional identities can change from cardholder to non-cardholder. The card can provide access to cheaper medicines under the Pharmaceutical Benefits Scheme, and a doctor may choose to bulk bill a holder. Other concessions vary by state, territory, local government and provider. Services Australia: “Benefits of a Commonwealth Seniors Health Card”

This is a genuine cliff effect. It does not mean that the person above the line suddenly became wealthy. It means that a continuous income variable has been converted into a binary status: eligible or ineligible.

2. The threshold does not measure a bank balance

“Income” is easy to misunderstand here. The CSHC does not simply count the cash received during the year and does not determine eligibility from total assets. Services Australia states that there is no assets test. The income test considers adjusted taxable income and adds deemed income from certain account-based income streams.

The Department of Social Services guide identifies components of adjusted taxable income that can include taxable income, total net investment losses, specified foreign income, employer-provided benefits and reportable superannuation contributions. Deeming rules can also apply to account-based income streams. DSS Social Security Guide: “Assessment of income for CSHC”

The figure $101,105 is therefore not a complete picture of how comfortably someone lives. It is an administrative construct for a particular purpose. It can include amounts that are not freely disposable cash in the present period and does not directly account for housing costs, medical needs, debt, regional prices, caring obligations or sudden expenditure.

This does not make an income test meaningless. Income is generally relevant to capacity to pay and is easier to administer than a comprehensive household-by-household assessment of need. The risk is that an operable proxy becomes mistaken for a precise measurement of real need.

3. Why must the system draw a line, and why here?

Public concessions cannot be distributed without rules. Government needs to define the intended group, estimate cost, process applications and treat similar cases with reasonable consistency. An income limit therefore serves three legitimate purposes: concentrating support on the group selected by policy, giving applicants and administrators advance notice, and avoiding an expensive and discretionary inquiry into every aspect of need.

The particular amount does not come from nature. It is the product of legislation and policy, and Services Australia reviews the test each 20 September in line with the CPI. The current figures are $101,105 for a single person, $161,768 combined for a couple, and $202,210 combined for a couple separated by illness, respite care or prison, with an additional $639.60 for each dependent child. Services Australia: “Income test”

Indexation prevents a fixed threshold from being eroded by inflation. It does not prove that this exact point corresponds to an objective discontinuity in need. The CPI tells the system how to move an existing line. It does not tell policymakers why the line originally belongs at that level or whether the value of the card is proportionate to the circumstances of households close to it.

This is a form of forced structure. Real need is multidimensional and continuous, while an administrative system compresses it into a small number of variables and enforceable categories. Construction is not itself a defect. The danger begins when a line built for operation is mistaken for reality itself.

4. The difference in consequence exceeds the difference in reality

An increase from $101,104 to $101,105 barely changes capacity to pay. Yet the CSHC is a status, not a cash payment that gradually reduces with income. A person who passes receives the card and its collection of concessions. A person who does not pass receives no card.

The loss is not the same for everyone. Someone who regularly uses prescription medicines may receive greater value. A person who rarely needs medicine and whose doctor does not bulk bill may receive less direct value. State and local concessions vary as well. “Losing the card” cannot be translated into one universal dollar loss.

That variation reveals a second design issue. The consequence is binary, but its value differs between people. The threshold does not measure medical use or regional concessions, yet it decides access to the package in one step.

Many cash benefits use a taper: as income rises, payment falls gradually. A taper reduces the chance that earning another dollar produces a larger net loss. A concession card is harder to taper because it confers a status linked to several prices and services. But “harder to taper” is a design constraint, not a complete answer about fairness. Policymakers can still consider a temporary retention period, a buffer, division of particular concessions or more gradual arrangements around the boundary.

5. Borderline cases involve more than the final dollar

Real disputes often arise not because a calculator added $101,104 incorrectly, but because the relevant income, reference period or life change was misunderstood.

The CSHC process ordinarily uses tax information from an earlier tax year. Someone may have just retired after a year of full-time wages. Another person may have received a one-off capital gain while current income is much lower. A historical figure can be accurate and still fail to represent present circumstances.

The guidance therefore permits a reasonable estimate of current-year income in specified circumstances, including retirement, partial retirement, illness, natural disaster or certain one-off events that make earlier income unrepresentative. The applicant must explain the change and provide supporting information. This is not a compassionate exception to the threshold. It recognises that the reference period itself can mismeasure the current case.

Other errors can arise from relationship status, dependent children, duplicate income, an incorrect account-based pension balance or misunderstanding the difference between adjusted taxable income and one figure on a tax return.

An adequate decision notice should therefore show the tax year used, the income components included, treatment of account-based income streams, the household limit applied, and the distance between the calculated amount and the threshold. “Your income is too high” is not enough to reveal what happened.

6. What can review correct—and what can it not change?

A person affected by an adverse Services Australia decision can ask for an explanation and seek formal review. An Authorised Review Officer reconsiders the facts, law and policy and can change an incorrect decision. Services Australia advises that many claim and entitlement decisions should be challenged within 13 weeks so that backdated entitlement is not limited even if the review succeeds. A person may then be able to seek review in the Administrative Review Tribunal. Services Australia: “Explanations and formal reviews of a Centrelink decision”

Meaningful review can correct inputs, family status, reference year, income classification, the reasonableness of an estimate and errors of law. It should allow current evidence rather than simply running the same calculation again.

Review cannot, however, change a valid legislative line out of sympathy. If verified income is at or above the limit, a reviewer cannot issue the card merely because the excess is one dollar. Individual review and system design do different work. A pattern of reasonable appeals that reviewers have no legal power to allow may itself be evidence that the threshold design needs reconsideration.

Conclusion: an eligibility line can remain without pretending to be the true boundary of need

An income limit serves a legitimate function. Without one, a concession system could become unpredictable, expensive and dominated by opaque discretion. The issue is not that the system uses the number $101,105. It is whether it extends the judgement supported by that number into a judgement the number cannot support.

One dollar can legally decide CSHC eligibility. It cannot prove that people on either side have materially different medical need or economic capacity.

My judgement is:

A clear income line can remain for a binary entitlement, but people near it should not bear a total loss grossly disproportionate to the difference in their real circumstances.

At a minimum, the system should provide an itemised calculation, accept evidence that reflects genuine changes in circumstances, offer human review with power to correct error, and regularly assess the distributional effect of both the threshold and the concession package. If one dollar creates a significant net loss, a retention period, buffer or partial taper deserves consideration.

Numbers can help government allocate resources. They should not be presented as ultimate knowledge of who truly needs help. A threshold is a public choice, and its designers remain responsible for explaining its location and correcting its consequences.

Primary sources

Discover more from Geoffrey Chen

Subscribe to get the latest posts sent to your email.