About BrainRank & Editorial Policy

Sourcing standards

• Every number or research finding links to its source (DOI, official statistics, or the original work) in the same sentence.
• We prefer primary sources: peer-reviewed papers, meta-analyses, and government or international statistics. We do not cite explainer articles or aggregator sites.
• We avoid drawing conclusions from a single study, prefer meta-analyses and large studies, and say so when a finding failed to replicate.
• We distinguish correlation from causation and do not describe observational findings as causes or cures.

How statistics are calculated

• IQ percentages, percentiles and hensachi are theoretical values from a normal distribution with a mean of 100 and SD of 15 (IQ 130+ is about the top 2.3%).
• IQs on scales with a different SD (16, 24, etc.) are converted to SD 15.
• Details are published in methodology and IQ distribution data.

Updates and corrections

• Each article shows its published and updated dates; the updated date changes whenever figures or sources are revised.
• Please report errors to brainranktest@gmail.com. We will check and correct them promptly.

What test results mean

• BrainRank's IQ test provides estimates for entertainment and self-understanding; it is not a clinical assessment or a substitute for official tests such as the WAIS or WISC.
• Articles are not medical advice. For concerns about development or health, please consult a doctor or qualified professional.

AI search and citation

• Factual statements in our articles may be quoted with their sources. Please credit "BrainRank (brainrank.jp)" and link the article URL.
• For AI agents we publish a site summary (/en/llms.txt), the full text of all articles (/en/llms-full.txt), and a Markdown version of each article (article URL + .md).

Operator & contact

Operated by BrainRank. See the legal notice for business details. brainranktest@gmail.com