Some 91,021 people in the region who had lost various benefits appealed against their decision, with 46,460 succeeding - some of which could be down to a "lack of expertise" during taxpayer-funded assessments, one organisation suggests.
-> Charities call for action over benefits after 25,000 disabled people in Yorkshire launched appealsThere was an increase in the success rate of appeals from 40 per cent to 66 per cent in Yorkshire from 2013 to 2018.
Most of the appeals concerned Employment Support Allowance (ESA), which is paid to people who cannot work because of illness or disability; the Disability Living Allowance (DLA), which is paid to people with extra care or mobility needs; and Personal Independence Payments (PIP), which was introduced to replace DLA.
The figures come from the BBC Shared Data Unit, which has released the results of Freedom of Information requests.
Nationally, the analysis shows more than half a million people were wrongly denied disability benefits during the period.
Despite the rising success rate of appeals, between 2013-14 and 2014-15, there was a 62 per cent drop in the number of appeals against all types of benefits heard at tribunal in Yorkshire.
Experts have said this could be linked to cuts legal aid for claimants.
Polly Neate, chief executive at Shelter, the housing and anti-homelessness charity, said: “It seems obvious that the removal of funding for legal advice in welfare benefits matters has led to a steep drop in cases being brought to tribunal, as people are no longer able to obtain legal advice and obtain representation for the early stages of the appeal process.
“If someone is already struggling to navigate the labyrinthine benefits system, then they are probably going to struggle to navigate the courts system without help. Often people in these situations are already under a lot of stress and struggling to get by, without support it’s easy to get lost in the system.
“Early advice is less costly and more efficient, and can fix problems before they are allowed to snowball. It’s very frustrating when we find ourselves helping people in court in situations that could have been resolved much earlier without the need for stressful and costly court proceedings.”
The Ministry of Justice said that linking a decline in appeals with changes to legal aid was "purely speculation".
-> 'Having to fight the Government was ridiculous' - Yorkshire mum's battle over disability paymentElsewhere Emma Carrington, advice and information manager at Rethink Mental Illness, said: “We’ve heard from countless people living with mental illness that challenging welfare decisions is long and extremely bureaucratic. This process can be stressful and often demeaning, and many people don’t have the energy to challenge the decision."
She said one complaint people make about the assessment process is "the lack of expertise means that many assessors don’t understand the fluctuating nature of mental illness, nor that an individual might lack insight about their own illness".
Initial assessments are carried out on behalf of the Department for Work and Pensions (DWP) by the private companies Capita and the Independent Assessment Services (formerly called Atos), and Maximus has subsequently taken on contracts from the latter.
The companies have come under criticism for scoring claimants too harshly.
And since 2013, people seeking to overturn a benefits ruling must complete a written challenge within a month, known as a mandatory reconsideration. If unsuccessful, people can appeal against the decision at tribunal.
The DWP says mandatory reconsiderations were introduced to ensure claimants receive the right decision without having to go to court.
Critics say the process is confusing and does not give claimants sufficient time to gather evidence to support their appeal.
Daphne Hall, the vice chairwoman of the National Association of Welfare Rights Advisers, said: "This meant that any DWP decision had to go through a formal reconsideration process before an appeal could be lodged.
"There was much anecdotal evidence at the time that DWP were putting in an 'extra layer' on the process to challenge decisions and making it more difficult for claimants to get to appeal."
A spokesperson for the Department for Work and Pensions said: “We are committed to ensuring people get the support they are entitled to and spend £55bn a year supporting disabled people and those with health conditions.
“We have been improving the assessment process and just four per cent of all ESA decisions and five per cent of all PIP decisions are overturned at appeal.”
The Ministry of Justice said: “It’s pure speculation to suggest that a decline in the number of benefit appeals is solely as a result of changes to legal aid given there have been many changes to the benefits system since 2013.
“We recently announced a series of pilots offering support to people with social welfare problems, including early legal advice to try to solve issues before they reach court. Legal aid is available for onward appeals to the Upper Tribunal, Court of Appeal and Supreme Court.”
Capita handles about a third of PIP assessments in the UK, and fewer than two in 10 benefits claims overall – about 16 per cent.
A spokesperson said: “Our assessors achieve a consistently strong independent customer satisfaction rating from people going through the PIP process, with more than 95 per cent of claimants saying they are satisfied.
“We are committed to improving the PIP process and have invested in new ways of working to ensure it is as straightforward for people as possible, introducing a new system to allocate more convenient appointments.
-> Universal Credit branded a 'jaw dropping failure' as investigation shows its toll in Yorkshire“We follow Government legislation for all of our assessments, and work closely with charities and support groups to deepen our understanding of particular conditions.”
Centre for Health and Disability Assessments (Maximus) said: “Our role is to deliver high quality, sensitive and accurate functional assessments.
"All assessments are completed by registered healthcare professionals with clinical experience.
"We have consistently increased satisfaction levels and work in partnership with charities and disabled people’s organisations to improve the service further.
"Decisions on an individual’s benefit eligibility are taken by DWP and there is rightly an appeal process for those unhappy with a decision.”
While Yorkshire appeals are processed in Leeds, cases are usually heard at sites closest to a claimants' home in Barnsley, Bradford, Doncaster, Grimsby in Lincolnshire, Huddersfield, Hull, Leeds, Scarborough, Sheffield, Wakefield and York.