Defence Home Ownership Assistance Scheme (Average House Price and Median Interest Rate) Determination 2018

The determination introduces several concepts that are critical to understanding how DHOAS subsidies are calculated. Average house price is a single dollar figure per financial year listed in the table in subsection 6. It does not differentiate by region, city, or dwelling type. The table covers eighteen financial years. The figures show a steady increase from $467,897 in 2008-2009 to $1,034,225 in 2025-2026, with a notable jump to $1,005,397 in 2022-2023 followed by a fall to $912,289 in 2023-2024 and then a rise again. These fluctuations mirror the ABS data on national median dwelling prices, but the determination fixes them as statutory numbers - they are not updated automatically or indexed. Median interest rate is defined by reference to the Act and the method in section 7. Under subsection 53(2) of the Act, paragraph (a) of that definition points to the interest rate worked out under this determination. The method in section 7 is purely mathematical: step 1 requires listing and numbering in ascending order the monthly interest rates published by Canstar for owner-occupier standard variable home loans offered by lending institutions on the authorisation day. If multiple institutions offer the same rate, they are listed alphabetically. Step 2 then finds the median: if the list has an odd number of entries, the middle rate is taken; if even, the two middle rates are averaged. The result is the median interest rate for that monthly authorisation period. Authorisation day and monthly authorisation period are terms defined in the Act (not in this determination) but are essential because they determine which interest rate snapshot is used. The determination does not define “owner-occupier standard variable home loans” - it relies on Canstar’s classification. That means Canstar’s internal product taxonomy directly influences the subsidy amount available to every eligible defence member. Canstar is named as the sole source of rate data. No alternative provider or fallback is specified in the instrument. This creates a single point of dependency and a potential monopoly on data that feeds the entitlement calculation. If Canstar changes its methodology, stops publishing, or is acquired, the Secretary may have no legally prescribed substitute. The concept of lending institutions is also left to Canstar’s identification; the instrument does not define which entities constitute lending institutions for this purpose. The determination thus delegates significant interpretive and informational control to a private corporation without any regulatory oversight or audit mechanism in the instrument itself.

The primary affected class is current and former members of the Australian Defence Force who are eligible for a home ownership subsidy under Part 2 of the Act. Each such member’s fortnightly subsidy is directly calculated using the average house price and the median interest rate determined under this instrument. Because the subsidy is calculated as a percentage of the notional interest payable on a loan amount up to the average house price at the median interest rate, both numbers directly influence the dollar value each member receives. Members in high-cost housing markets (e.g. Sydney, Melbourne) may find that the national average house price is below their actual purchase price, so the subsidy caps are less useful to them. Members in lower-cost areas may fare better relative to local prices. The Secretary of the Department of Defence (or their delegate) is the decision-maker who must apply these figures each month. The Secretary must use the correct average house price for the financial year in which the member’s loan was authorised and must recalculate the median interest rate monthly using Canstar data. Administrative staff must have access to Canstar’s published rates and correctly apply the step method in section 7. Lending institutions whose owner-occupier standard variable home loan rates are collected by Canstar are indirectly affected. Their rate offerings form part of the dataset from which the median is calculated, and therefore their pricing decisions can influence the subsidy cap for thousands of members. However, the instrument does not impose any duty on lenders to supply data or to maintain their rates in any particular way - they are passive participants. Canstar Pty Limited is directly affected as the sole mandated data source. The instrument implicitly grants Canstar a statutory role in the administration of a Commonwealth scheme. This may have commercial value for Canstar (e.g. reputational, data licensing) and raises potential competition concerns if other data providers are excluded without a procurement process. Taxpayers are ultimately affected because the subsidy amount is a government expense. If the average house price is set too high relative to actual market conditions, the subsidy cost to the budget increases. Conversely, if the median interest rate is calculated in a way that yields a higher rate, the subsidy per member also rises. The determination does not include any cost-impact statement or fiscal note, but the raw numbers - especially the $1 million plus cap for 2025-2026 - indicate substantial potential outlays.

This determination does not itself impose duties or confer rights on any person. The operative legal duties and rights are found in the Act. However, the determination creates an administrative framework that conditions those rights and duties. The Secretary has a duty under the Act (section 52 and section 53) to use the average house price and median interest rate as determined under this instrument when calculating the subsidy. That duty is non-discretionary: the Secretary must apply the precise figure from the table for the relevant financial year and must follow the median interest rate method in section 7. This duty extends to ensuring that the correct authorisation day is used for each monthly authorisation period and that Canstar’s published rates are accurately transcribed. Eligible members have a right to have their subsidy calculated using the correct parameters. If the Secretary applies a wrong average house price or an incorrectly calculated median interest rate, a member may have a right to seek review and correction under the Act’s internal reconsideration mechanism or through the Administrative Appeals Tribunal (now the Administrative Review Tribunal). The determination does not create any obligation on lending institutions or on Canstar. Canstar has no statutory duty to continue publishing the rate data, nor to ensure its methodology remains consistent. The instrument assumes that data will be available without interruption. If Canstar were to stop publishing, the Secretary would have no lawful basis to calculate the median interest rate under this instrument, potentially stalling the entire subsidy system. That is a notable structural gap. No rights of review are created directly under the determination; review rights flow from the Act. The determination does not require the Secretary to publish the median interest rate calculated each month, nor to disclose the underlying Canstar data used. That lack of transparency may hinder members from verifying that their subsidy was correctly computed. In practice, a member would have to request Canstar’s data themselves or rely on the Department to release it. The determination also does not specify a mechanism for correcting errors if Canstar later amends its published rates for a given month.

The instrument contains no penalty provisions. It is a purely computational legislative instrument. Any enforcement consequences arise from the underlying Act. For example, a member who provides false information to obtain a subsidy may be liable for criminal penalties under the Criminal Code or civil penalties under the Act, but those are not part of this determination. The Secretary or the Department could be subject to judicial review under the Administrative Decisions (Judicial Review) Act 1977 if the median interest rate is miscalculated or the wrong average house price is applied. A court could set aside the decision and require recalculation. There is no mechanism for private enforcement of the determination itself. Non-compliance by the Secretary is not an offence; it would be an error of law that could be corrected through the administrative law system. The determination does not confer standing on any party to enforce compliance directly. The use of the determination as a legislative instrument means it is subject to tabling and disallowance under the Legislation Act 2003. If either House of Parliament disallows it within the disallowance period, the determination would cease to have effect, and the Act would revert to having no average house price or median interest rate method - effectively halting the scheme until a new instrument is made. That is a political enforcement tool, not a legal one. The determination does not require any annual review or sunset clause. It remains in force until repealed or replaced. There is no penalty for Canstar if it fails to publish rate data or if its data is inaccurate. The instrument does not require Canstar to verify, audit, or license its data. This absence of accountability for the data provider is a vulnerability.

The determination is made under the Defence Home Ownership Assistance Scheme Act 2008 and must be read as part of that statutory scheme. Sections 52 and 53 of the Act require the determination to set the average house price and the median interest rate. The definitions in the Act (e.g. “authorisation day”, “monthly authorisation period”) are incorporated by reference. The determination does not repeat those definitions, so the reader must cross-refer to the Act. The instrument is subject to the Legislation Act 2003, which governs the registration, tabling, and disallowance of legislative instruments. It is a legislative instrument and therefore must be registered on the Federal Register of Legislation. It is also subject to scrutiny by the Parliamentary Joint Committee on Human Rights and the Senate Standing Committee for the Scrutiny of Delegated Legislation. Under the Acts Interpretation Act 1901 (and its successor the Legislation Act 2003), the determination must be published and may be subject to sunset rules (though this instrument likely has a self-repealing effect when a new determination is made - it does not expressly sunset itself). The determination interacts with the Public Governance, Performance and Accountability Act 2013 (PGPA Act) in two respects. First, the reliance on Canstar as a sole data provider could be viewed as a procurement of information services, which may be subject to the Commonwealth Procurement Rules. The instrument does not indicate any competitive process or value-for-money assessment for appointing Canstar. Second, the subsidy payments themselves are government expenditure subject to the PGPA Act’s requirements for proper use of money. The determination may also interact with the Competition and Consumer Act 2010 if the exclusive designation of Canstar is seen as anti-competitive. No other provider has a statutory right to supply the rate data, even if its data is more comprehensive or accurate. That could raise concerns under the Competition and Consumer Act’s prohibition on anti-competitive conduct, though as a government instrument it may be exempt. The determination does not interact directly with state or territory laws. State property and lending laws apply to home loans received by members but are independent. In summary, the determination sits within a web of federal administrative, procurement, and financial legislation, but its drafting is silent on most of those interactions, leaving implementation risks.

The source text does not contain any amendment history. The instrument is titled “Defence Home Ownership Assistance Scheme (Average House Price and Median Interest Rate) Determination 2018”. The lack of any amendment note or schedule suggests it is the original version as made in 2018. However, because the table includes figures for financial years through 2025-2026, it is likely that the determination has been remade or amended at least once since 2018 to update the forward years; the table as shown includes 2024-2025 and 2025-2026, which were future years at the time of original making. It is possible that later amending determinations added those rows. But the source provided does not list any amending instruments. A practitioner should check the Federal Register of Legislation for the current compilation. The absence of amendment history in the source is a gap - users cannot verify whether the table has been updated or whether the median interest rate method has been changed. The instrument is subject to the Legislation Act 2003 section 44, which requires the rule-maker to maintain a compilation record. As an analyst, I cannot assume that the source is the up-to-date version. The safest assumption is that this is the text as at the date the user provided, but any litigation or compliance work should confirm the current law.

The source text does not mention any cases. There is no litigation history referenced in the determination itself. This is unsurprising given the instrument’s narrow administrative nature. Challenges would typically be taken against decisions applying the wrong numbers, not against the instrument itself. A person could hypothetically seek judicial review of the determination on the grounds that it was made beyond the power granted by sections 52 and 53 of the Act (e.g. if the average house price was not “averaged” in any recognisable sense) or that the median interest rate method fails to produce a genuine “median”. The High Court of Australia could consider whether the delegation of the median calculation to a private entity (Canstar) is constitutionally permissible, though no such case is reported. The Administrative Appeals Tribunal (now ART) may have considered individual subsidy decisions that turned on the correct application of the determination, but those decisions would not directly interpret the instrument. The absence of litigation history does not mean the instrument is beyond challenge, only that no reported cases exist in the source. Future litigation might address the use of a single private data source in statutory scheme, or the rigidity of the forward-fixed house prices. Until such cases arise, the determination remains untested in court.

Several subtle features and gaps deserve close attention. First, the average house price for a financial year is fixed at the time the determination is made. For 2025-2026, the figure $1,034,225 was set years in advance. If actual national median house prices in 2025-2026 are higher or lower, the subsidy cap does not adjust. This can create either an unintended windfall or a shortfall for members. The determination does not include a trigger for update if actual prices deviate, nor does it index the figures to any published index. Second, the median interest rate method relies entirely on Canstar’s classification of “owner-occupier standard variable home loans”. Canstar’s product definitions may change without notice. The instrument does not require Canstar to maintain a consistent methodology, nor does it provide a fallback if Canstar changes its definitions in a way that materially alters the median rate. Third, there is no requirement for the Secretary to publish the monthly median interest rate or the underlying data. Members cannot easily verify the rate used. If the Secretary miscalculates, the error may go unnoticed. Fourth, the method for even-numbered lists takes the average of the two middle rates. That arithmetic average may produce a rate that no institution actually offers, which is theoretically acceptable but may misrepresent the market. Fifth, the definition of “lending institutions” is left to Canstar to determine. If Canstar includes institutions that are not regulated by APRA or that offer non-standard products, the median could be distorted. Sixth, the instrument does not address what happens if Canstar ceases to publish rate data, is acquired, or goes out of business. The Secretary would have no lawful means to calculate the median interest rate. Seventh, the determination’s provisions are silent on rounding - should the median be expressed to one, two, or three decimal places? The only example in the note (section 7) uses one decimal place (4.7%), but the formula gives 4.7% as the exact average of 4.6 and 4.8. If the two middle rates are 4.65% and 4.70%, the result would be 4.675%. The instrument does not specify rounding rules. Eighth, the authorisation day is defined in the Act; the determination does not define it again, but a practitioner must check the Act to understand which day triggers the monthly snapshot. If the authorisation day falls on a weekend or public holiday and Canstar’s data for that day is not published until the next business day, the Secretary may be forced to use stale data. Ninth, the instrument has no transitional provisions. If it is replaced by a new determination, the old determination’s average house price for a financial year that has already commenced may not align with the new determination’s figure. Uncertainty could arise mid-year. Tenth, the determination does not include any provision for correction of errors if Canstar issues a revised rate for a given month after the subsidy has already been paid.

Compliance obligations fall almost entirely on the Secretary of the Department of Defence. The Secretary must ensure that, for each monthly authorisation period, the median interest rate is correctly calculated in accordance with the steps in section 7. This requires obtaining Canstar’s published list of monthly interest rates for owner-occupier standard variable home loans as at the authorisation day. The rates must be listed in ascending order. If duplicate rates exist, the institutions offering them must be listed alphabetically. The Secretary must then determine whether the list has an odd or even number of entries and apply the appropriate formula. The result must be recorded and applied to all subsidy calculations for that month. The Secretary must also ensure that the correct average house price from the table in section 6 is used for the financial year in which the member’s loan was authorised. The table is organised by financial year; the Secretary must identify the correct year and apply the corresponding dollar figure. The determination does not specify how to treat loans that straddle financial years, but the Act likely sets the authorisation day determines the year. Eligible members do not have direct compliance duties under this determination, but they have a practical interest in verifying that the subsidy they receive appears to be based on the correct numbers. They can request the Department to explain how the median interest rate and average house price were applied. If the subsidy seems too low, they should check the relevant financial year and confirm the average house price. They can also monitor Canstar’s published rates to see whether the median rate the Department used aligns with a rough median they can derive. Lending institutions have no duties under this instrument, but they may choose to monitor their own rates and how they affect the median. If they believe the median is being distorted by another institution’s rate, they have no recourse under this instrument. Canstar has no statutory duties, but as a matter of commercial practice it should maintain transparency and consistency in its data collection and product classification to avoid legal challenge. Legal and compliance professionals advising the Department should ensure that the determination is the most up-to-date compilation; that the median interest rate method is documented and auditable; that data from Canstar is preserved each month in case of later dispute; and that any rounding policy is consistently applied even though the instrument is silent. They should also consider drafting a contingency for Canstar data failure, such as a fallback to the Reserve Bank of Australia indicator lending rates, though that would require amending the determination. In practice, the compliance burden is low: one monthly data collection and calculation, plus correct use of the fixed table. But the compliance risk is moderate because the Secretary has no margin for error - a miscalculation of even 0.01% in the median interest rate, multiplied across thousands of members, could result in significant overpayment or underpayment that must be corrected administratively with potential costs to the Commonwealth or individual members.