Mensa is the world's oldest and largest high-IQ society, welcoming individuals who score in the top 2% of the population on a standardised intelligence test. This comprehensive guide covers the history of Mensa, membership requirements, Barnet's connection to Mensa, and everything you need to know about testing in Barnet.

Last Updated: August 2026

The History of Mensa

The Founding: Oxford, England (1946)

Mensa was founded in 1946 at Oxford University in England by two remarkable individuals: Roland Berrill, an Australian barrister, and Dr. Lancelot Ware, a British scientist and lawyer. The two met by chance on a train journey and discovered they shared a common interest in intelligence testing. They decided to form a society for people with high IQs, and the result was Mensa.

The name "Mensa" comes from the Latin word for "table," symbolizing the organization's goal of creating a round-table society where members meet as equals regardless of background, occupation, race, or any other characteristic. The only qualification for membership is intelligence.

The Early Years

Mensa grew slowly at first but steadily gained recognition. By the 1960s, the organization had established chapters in several countries, including the United Kingdom. Today, Mensa has grown to over 150,000 members across more than 100 countries, making it the largest and oldest high-IQ society in the world.

British Mensa, the UK chapter, now boasts over 50,000 members, representing one of the largest national groups within Mensa International.

Mensa's Three Purposes

Mensa has three stated purposes:

• To identify and foster human intelligence for the benefit of humanity
• To encourage research into intelligence and its characteristics
• To provide a stimulating intellectual and social environment for its members

Barnet’s Connection to Mensa

British Mensa serves members across the UK, including Barnet. Qualification is based on top-two-percent performance rather than residence, profession or education. Local social activity can change from year to year, so current meetings should be checked through Mensa’s official member and event channels.

Barnet's international population, universities, research institutions, professional communities, and multilingual culture create a broad audience for high-IQ societies. Barnet-area residents participate through British Mensa's England local-group network. Official chapter boundaries, testing sessions, events, and contacts can change, so applicants should use the British Mensa directory rather than relying on an unofficial local membership estimate.

British Mensa Qualification Thresholds

British Mensa’s core criterion is performance in the top two percent of the population on an accepted route. Because different tests use different scales and because prior-evidence rules can change, this guide does not copy a fixed list of American historical score cut-offs and present it as current UK policy.

What “top two percent” means

The 98th-percentile principle is a rank within an appropriate reference group, not a promise that every test expresses qualification as the same numerical IQ. Test scales, editions and score types differ, so the receiving organisation’s current rule controls.

The supervised session is a membership-selection test, not a clinical diagnostic evaluation. British Mensa currently describes supervised sessions as taking about two and a quarter hours under controlled conditions.

Mensa in Barnet

British Mensa membership

British Mensa accepts people who demonstrate an IQ in the top two percent through its supervised testing options or qualifying prior evidence. Membership statistics should not be converted into a supposed citywide IQ ranking.

• qualification is based on an accepted top-two-percent result, not postcode
• a supervised Mensa test and a private clinical evaluation serve different purposes
• prior evidence must satisfy Mensa’s current documentation rules
• membership does not diagnose giftedness, disability or any clinical condition
• local participation can include regional events, special-interest groups and national activities

Who Takes the Mensa Test in Barnet?

Test-takers include curious adults, students, parents seeking information for older children and people who want formal evidence for membership. The motivation is personal; Mensa testing is not a clinical diagnosis, school placement decision or employment assessment.

• adults testing primarily for personal curiosity or membership
• students interested in a formal reasoning benchmark
• older children eligible for Mensa’s supervised route under current age rules
• families considering prior evidence from an educational psychologist for younger children
• people who already hold a professional report and want to check whether it can be submitted

Barnet Mensa Events

British Mensa organises member activities and interest groups nationally and regionally. Event dates and venues change, so this page does not invent a fixed local calendar.

Accepted Tests for Mensa Qualification

Prior evidence from psychologists

British Mensa publishes its own current prior-evidence rules. Before booking a private psychologist, ask Mensa whether the intended test edition, score and report format are acceptable. WISC, WAIS and Stanford-Binet families have different editions and norm systems, so the exact instrument matters.

• the examinee’s name and identifying information should be clear
• the exact test family and edition should be stated
• the qualifying score or percentile must be documented in the form Mensa accepts
• the administration date and age at testing should be available
• the practitioner’s professional details should be identifiable
• submit the full evidence Mensa requests rather than a self-created score screenshot

School-administered measures

School attainment, CAT-style screening or admissions tests are not automatically Mensa-qualifying evidence. Only submit evidence that meets the organisation’s published criteria.

• school grades describe attainment rather than necessarily providing an accepted IQ score
• 11+ or independent-school entrance papers are admissions tools
• group cognitive screening may have a different purpose and evidence standard from individual testing

College and admissions tests

University admissions examinations measure programme-relevant skills and are not interchangeable with an individually administered clinical intelligence test unless Mensa explicitly lists a particular historical score route.

The Mensa Testing Process

Two Ways to Qualify

• Supervised Mensa testing: book through British Mensa and follow its current testing arrangements.
• Prior evidence: submit qualifying evidence from an accepted assessment under Mensa’s published rules.
• Age check: confirm whether the applicant is old enough for the supervised route or needs prior evidence.
• Documentation check: verify the accepted evidence before commissioning a private assessment.
• Result handling: keep the original professional documentation rather than relying on an informal summary.
• Membership step: a qualifying result leads to an invitation; it is not itself a clinical diagnosis or educational placement decision.

The Mensa Supervised IQ Test

British Mensa states that supervised testing is available in person or online and that qualification requires performance in the top two percent. Current session length, fees and booking arrangements should be checked on the Mensa website.

What the Mensa Test Measures

Mensa’s current testing options assess reasoning ability for membership selection. They do not provide the same clinical history, diagnostic formulation or recommendations as a psychologist’s comprehensive evaluation.

Important: The Test is for Admission Only

A Mensa admissions result answers the membership question. It should not be used to diagnose ADHD, autism, dyslexia, dementia, acquired brain injury or any other condition.

Frequently Asked Questions