Prior to election day, the AEC predicts who the two candidate preferred (TCP) candidates will be in order to enable the TCP count for each of the 151 divisions across the country to be conducted on election night.

The TCP prediction is often based on previous election results within the relevant division. If, after the count, it becomes clear the predicted TCP candidates are incorrect, the AEC will mask the results from the TCP count on the Tally Room. This is referred to as a TCP Exception.

A fresh TCP count will be conducted and preferences distributed to the correct two leading candidates in the days following the election night count.

These are different terms, though they can often, but not always be interchanged.

The term 'two candidate preferred' (TCP) refers to a distribution of preferences (votes) between two candidates who are expected to come first and second in the election. Often the two candidates for the TCP process will be from the ALP and the Coalition, but it could also be candidates from minor parties or independent candidates depending on who is expected to gain the majority of votes.

The term 'two party preferred' (TPP) refers to a distribution of preferences (votes) between the two major parties – the ALP and the Coalition (Liberal/National parties). This comparison is usually used to try to predict the possibilities of forming a government. It is a tool that examines the proportion of votes that will go to the major parties after all preferences have been taken into consideration.

The initial scrutiny (count) of House of Representatives ballot papers conducted at the polling place on election night is followed by a 'fresh scrutiny' conducted at a divisional out-posted centre in the days following election day.

The fresh scrutiny is a re-check of all ordinary House of Representatives ballot papers received from every polling place, pre-poll voting centre and mobile polling team within a division.

The fresh scrutiny is an important step, required by the Commonwealth Electoral Act 1918 (Electoral Act), to further ensure the accuracy of the counting process. The fresh scrutiny is a process managed by permanent AEC staff.

A recount may be undertaken, approved or directed at any time before the result of an election is declared.

In the case of a House of Representatives election, if the margin of votes between the first and second ranked candidates at the completion of the distribution of preferences is less than 100 votes, a full recount of all formal and informal ballot papers is conducted as a matter of course.

A recount is not the same as the routine re-check (fresh scrutiny) of the House of Representatives votes that were counted on election night.

The distribution of preferences is the final result of the House of Representatives election and consists of a series of candidate exclusions. The distribution is achieved by progressively excluding candidates with the least number of votes. The exclusions continue until only two candidates remain.

An example of a distribution of preferences is available.

The distribution of preferences takes place in every electoral division as required by the Commonwealth Electoral Act 1918. The distribution of preferences does not commence until the counting of all ballot papers has been completed.

A distribution of preferences takes place in every division and is used to calculate the two party preferred statistics for divisions that have ALP and Coalition as the final two candidates. In divisions that do not have the ALP and Coalition as the final two candidates, a Scrutiny for Information is conducted to determine the two party preferred result.

A scrutiny for Information in such cases is a notional distribution of preferences to find the results of preference flows to the ALP and Coalition candidates.

Counting in a federal election continues for some time after polling day.

On election night, both ordinary ballot papers, and pre-poll ballot papers completed by voters within their division, are counted to first preferences. The AEC also conducts a Two Candidate Preferred (TCP) count of House of Representatives ballot papers on election night, which helps give an indication of the likely outcome of the election.

After polling day, the declaration votes (absent and pre-poll votes) are sent to their home divisions. During the first week after polling day, scrutiny (checking of voter eligibility and counting) of absent, pre-poll, provisional and postal votes begins.

The AEC is obliged under the Commonwealth Electoral Act 1918 to wait 13 days for declaration votes to arrive. These must be forwarded to the home division (where relevant). In the case of a close seat, this may mean that a result may not be available until after the 13 days have elapsed.

• More details about counting the votes

If you vote above the line on the Senate ballot paper you are choosing to vote for parties and/or groups rather than individual candidates. Your preferences will first be distributed to the candidates in the party or group of your first choice, then to candidates in the party or group of your second choice and so on, until all your preferences have been distributed.

The Commonwealth Electoral Act 1918 (Electoral Act) contains specific requirements that must be met by voters in marking their ballot papers to be included in the count for a federal election. When casting a vote it is important that voters follow the instructions specified on the Senate and House of Representatives ballot papers to ensure that their vote is able to be included in the count. If voters do follow the voting instructions then there is no risk to their vote being classified as informal and not being counted.

There are vote-saving provisions in the Electoral Act that allow some ballot papers to be included in the count even though the voting rules have not been fully met.

For House of Representatives ballot papers the requirement for a formal vote is that every square must contain a consecutive number for all candidates on a ballot paper to be a formal vote (see section 240 of the Electoral Act). This is the instruction that is printed on these ballot papers. However, there is a vote-saving measure that can operate where one square is left blank and where preferences for all other candidates have been marked with a consecutive number (see paragraph 268(1)(c)).

For Senate ballot papers the requirement for a formal vote is that when voting above the line, at least the numbers 1 to 6 shall be marked in the squares on the ballot paper (see subsection 239(2)). For voting below the line, the requirement is that at least the numbers 1 to 12 are marked in the squares printed on the ballot paper (see subsection 239(1)). However, there is a vote savings measure that can operate where only one square is marked above the line (see section 269), or where voting below the line, at least six squares have been marked 1 to 6 using consecutive numbers (see section 268A).

After the first preferences are counted on election night, a check of Senate ballot papers is undertaken at the office of each Divisional Returning Officer. This occurs in the days following election day.

The ballot papers are then sent to a central location known as the Central Senate scrutiny. When all preferences are captured, a computerised scrutiny system is used to calculate the quota, distribute preferences and determine the results.

The quota for a Senate contest cannot be calculated until the state or territory-wide total of all votes is known.

Results for Senate contests have always taken longer than the House of Representatives – final results are often not known until three or four weeks after election day. This reflects the size and nature of the task as well as allowing for the legislative timeframe for the return of postal and declaration votes to home electoral divisions.

In a Senate contest every single vote must be included in the count for the distribution of preferences to occur with all votes scanned, verified and stored by AEC polling officials with appropriate scrutiny arrangements in place.

• Indicative timeline for Senate counting process diagram