The legal standard a provisional must meet
Many inventors are surprised to learn that the law sets a standard for provisional specifications at all. Section 40(1) of the Patents Act 1990 requires a provisional specification to disclose the invention in a manner that is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art. This wording was introduced by the Raising the Bar reforms in 2013, which deliberately brought Australia into line with Europe and the United Kingdom.
Before 2013, a provisional only had to "describe" the invention, and claims in the complete application needed only to be "fairly based" on it. That more forgiving test is gone. A provisional now has to enable a skilled person to put the invention into practice, which is the same disclosure standard that applies to a complete specification under section 40(2)(a).
Nobody tests this when the provisional is filed. IP Australia does not examine provisionals, and a provisional that falls well short of the standard is accepted just as readily as one that meets it. The problem only surfaces when someone relies on the priority date.
Priority is decided claim by claim
The priority date of each claim in your complete application is assessed separately. Under section 43 and the Patents Regulations, a claim takes the provisional's filing date only if the provisional disclosed the invention defined by that claim clearly enough and completely enough for it to be performed. If the provisional doesn't disclose a feature that the claim relies on, that claim falls back to the date the complete application was filed.
This is why a patent can end up with claims of several different priority dates. A broad claim might be entitled to the provisional date, while a narrower claim that adds a feature first described in the complete application is not. The narrower claims are often the ones you need most, because they are the fallback positions you retreat to when the examiner cites prior art against the broad claims.
A priority date isn't given to the application as a whole. Each claim earns it, or doesn't, depending on what the provisional actually disclosed.
How the gap becomes dangerous
The 12 months between the provisional and the complete application is meant for commercial activity. You launch the product, talk to investors, publish your results and demonstrate the invention at trade shows. All of that is safe if the claims you eventually pursue are entitled to the provisional date.
If they are not, every one of those activities becomes prior art against them. So do any patent applications competitors filed during the gap, and any articles or products that appeared in it. A claim that would have been plainly new at the provisional date can turn out to be anticipated, or obvious, at the later date.
The ToolGen CRISPR case shows how strictly the courts apply this. In ToolGen Inc v Fisher (No 2) [2023] FCA 794, the earliest priority document described a gene-editing system built from components of one particular bacterium, while the claims covered the technique more broadly. The Federal Court held that the earlier document did not disclose the broader invention clearly and completely enough, so the claims lost the earliest date. Material published in the intervening months then left the application without a valid claim.
When your own disclosure is used against you
The worst version of this scenario involves your own publicity. Suppose you file a two-page provisional, launch the product a month later with a detailed brochure and video, and file the complete application at 12 months with the full technical detail added. If the key claims don't get the provisional date, your own brochure and video were published before the date those claims now rely on.
In Australia, a 12-month grace period can disregard an inventor's own disclosures, provided the complete application is filed within 12 months of them. That can rescue the Australian application, but it is not a general safety net. Europe and China have no comparable general grace period, so in those markets your own launch can destroy novelty outright. And the grace period never covers what other people published or filed in the gap, even if they were working on the same problem independently. We compare the rules in the main markets in patent grace periods country by country.
Why it usually can't be fixed later
Many self-filers believe a thin provisional can be fixed when the complete application is prepared. Detail and claims can certainly be added at that point, but anything added only takes the date of the complete application. Nothing can be backdated to the provisional.
Once the complete application is filed, section 102 of the Patents Act prevents amendments that would claim or disclose matter not in the specification as filed. So there are two cut-off points: what is in the provisional decides what gets the early date, and what is in the complete specification decides what can be claimed at all.
The only way to protect an improvement developed during the provisional period is to file a further provisional for it, or to include it in the complete application, and either way it gets a later date. That is useful for genuine improvements made after filing, as we explain in capturing improvements during the provisional period. It does nothing for detail about the original invention that was simply left out.
How to avoid these pitfalls
The answer is to prepare the provisional as if it will be examined, because in effect it will be, years later and with the benefit of hindsight. That means describing the invention in real technical detail, with the alternatives and variations you might want to claim, and drafting claims at the provisional stage so that each claimed feature is clearly disclosed from day one. We set out the practical steps in can you prepare a patent application yourself? and cover other common errors in common mistakes inventors make when filing a provisional patent.
If you have already filed a provisional yourself and are worried it may not be sufficient, talk to us before you disclose the invention any further. Depending on the timing, a properly prepared further provisional may still protect your position. Contact Patentec for a free initial consultation.