Judgements around how best to fairly include candidates in any proposed mayoral debate are based on the 大象传媒’s election guidelines, which include the requirements of Ofcom (the 大象传媒’s regulator) and may be found here.
Editorial judgement lies at the heart of any decision which involves giving some candidates more coverage than others - but that must take into account an objective look at the past and current electoral support of parties and candidates in each area. So those with a record of some support, especially in previous equivalent elections, may often be given more time and prominence than those who have not attracted electoral support before. However, opinion polls, indicating more current support, can also be a factor - the 大象传媒’s Editorial Guidelines say that “the findings of voting intention polls must be reported in the context of trend”, so where a party or candidate has established a robust and consistent trend of such support, that too will be taken into account.
One important reason for having debates is that voters have the opportunity to question and scrutinise a person who could be in power and help hold them to account for what they intend to do with that power. If every debate always involved all the candidates equally, even when sometimes that might mean double-figures of participants competing for attention, that would mean less opportunity to hear enough from those candidates most likely to win and exercise political power.
So involvement in debates (and other election output) is proportionate - in other words, candidates such as those from the larger parties and others with a track record of past or current support amongst their electorate are more likely to take part fully in debates. Others, with less evidence of support - or perhaps none - will still have involvement of some sort, perhaps a short pre-recorded statement or interview, but it may sometimes be limited simply to a reminder during or after the debate about the full list of candidates standing. That might also mean signposting the audience to other programmes or places online where they can find out more about all of the candidates.
There may be other relevant factors too; sometimes, a candidate might stand for the office of mayor to draw attention to a particular cause, or may only propose policies which have limited or no relevance for the mayor’s powers. Whilst it is important that broadcasters tell voters about such candidates, a debate with all the other candidates may not be the most appropriate way, if they do not have the necessary evidence of electoral support.
Editors should try to make fair judgements, mindful of the 大象传媒's obligations of due impartiality and in the best interests of voters as a whole. Advice is available to make sure those decisions are taken with appropriate consistency and are taking into account all appropriate factors, such as those mentioned above. There will not always be agreement with what editors decide and candidates who feel they’re not being treated fairly can, of course, bring forward evidence of support to challenge such judgements and - if necessary - use the formal process to complain.