Sources: The Research and Reference Works Behind Every Page

Chapman's love-language framework is a popular vocabulary with little peer-reviewed support for matching; astrology and numerology are traditions with no evidence of predicting compatibility; attachment is a well-studied framework.

Every claim on this site that begins "research shows", every framework a quiz is built on, and every rule a Tradition tool applies, links to something on this page. The rules themselves are set out under how we calculate it.

Which sources does LoveCalculator.love accept?

LoveCalculator.love accepts primary sources: peer-reviewed papers and original books first, and the traditions' own reference works for the traditions. No blog summaries, no social posts and no content farms are cited for a fact.

Three rules apply to every entry:

Opened by a person. A source counts as verified only after a person has opened it and checked every field, a rule set by our editorial policy. Each entry below shows its status: "Verified" with the date of the check, or "Being verified". An entry that is being verified has not passed the check yet, and no page may rest a claim on it until it has.
Evidence status stated. Each group ends with one plain sentence on what the evidence supports.
No weak source for a popular claim. Where a popular claim has no source we could find, we say so instead of repeating it.

If a citation here is wrong or a link is dead, that is a correction: info@lovecalculator.love.

Which sources does LoveCalculator.love cite, by topic?

LoveCalculator.love cites sources in nine topic groups: love languages, relationship science, attachment, Western astrology, Vedic astrology and kundli matching, the Chinese zodiac, numerology, FLAMES and the paper love games, and the history of name-based calculators and love testers. Each group lists its entries, then its evidence status, then the pages that use it.

A. Love languages

L1. Chapman (1992)

Chapman, Gary. The Five Love Languages: How to Express Heartfelt Commitment to Your Mate. Chicago: Northfield Publishing, 1992.

Type: Primary book (the framework). Status: Verified 2026-09-22 against the Open Library catalogue record.

L2. Impett, Park and Muise (2024)

Impett, Emily A., Haeyoung Gideon Park and Amy Muise. "Popular Psychology Through a Scientific Lens: Evaluating Love Languages From a Relationship Science Perspective." Current Directions in Psychological Science, 2024, vol. 33, no. 2, pp. 87 to 92. https://doi.org/10.1177/09637214231217663

Type: Peer-reviewed review. Status: Verified 2026-09-21 against the Crossref record.

L3. Egbert and Polk (2006)

Egbert, Nichole and Denise Polk. "Speaking the Language of Relational Maintenance: A Validity Test of Chapman's Five Love Languages." Communication Research Reports, 2006, vol. 23, no. 1, pp. 19 to 26. https://doi.org/10.1080/17464090500535822 Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record.

L4. Bland and McQueen (2018)

Bland, Andrew M. and Kristen S. McQueen. "The Distribution of Chapman's Love Languages in Couples: An Exploratory Cluster Analysis." Couple and Family Psychology: Research and Practice, 2018, vol. 7, no. 2, pp. 103 to 126. https://doi.org/10.1037/cfp0000102

Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record (the journal and volume were corrected on this date: the draft cited The Family Journal, vol. 26).

L5. Hughes and Camden (2020)

Hughes, Jamie L. and Abigail A. Camden. "Using Chapman's Five Love Languages Theory to Predict Love and Relationship Satisfaction." Psi Chi Journal of Psychological Research, 2020, vol. 25, no. 3, pp. 234 to 244. https://doi.org/10.24839/2325-7342.jn25.3.234 Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record.

Evidence status: Chapman's framework is a widely used vocabulary for talking about affection. The peer-reviewed review by Impett, Park and Muise (2024) found that the research does not provide strong support for the book's three central assumptions: that each person has a preferred love language, that there are five love languages, and that couples are more satisfied when partners speak one another's preferred language. The test on this site is a self-reflection tool, not a measurement of a relationship.

Trademark note: "The 5 Love Languages" is a registered mark of its owner; this site uses the descriptive phrase "love language test", credits the book, and uses its own questions.

Used on: Love Language Test, What Is My Love Language?.

B. Relationship science: stability, satisfaction, similarity

R1. Gottman and Levenson (1992)

Gottman, John M. and Robert W. Levenson. "Marital Processes Predictive of Later Dissolution: Behavior, Physiology, and Health." Journal of Personality and Social Psychology, 1992, vol. 63, no. 2, pp. 221 to 233. https://doi.org/10.1037/0022-3514.63.2.221 Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record.

R2. Gottman (1994)

Gottman, John M. What Predicts Divorce? The Relationship Between Marital Processes and Marital Outcomes. Hillsdale, NJ: Lawrence Erlbaum Associates, 1994.

Type: Primary book (the Four Horsemen). Status: Verified 2026-09-22 against the Open Library catalogue record.

R3. Gottman and Levenson (2000)

Gottman, John M. and Robert W. Levenson. "The Timing of Divorce: Predicting When a Couple Will Divorce Over a 14-Year Period." Journal of Marriage and Family, 2000, vol. 62, no. 3, pp. 737 to 745. https://doi.org/10.1111/j.1741-3737.2000.00737.x Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record.

R4. Gottman and Silver (1999)

Gottman, John M. and Nan Silver. The Seven Principles for Making Marriage Work. New York: Crown, 1999.

Type: Practitioner book. Status: Verified 2026-09-22 against the Open Library catalogue record.

R5. Montoya, Horton and Kirchner (2008)

Montoya, R. Matthew, Robert S. Horton and Jeffrey Kirchner. "Is Actual Similarity Necessary for Attraction? A Meta-Analysis of Actual and Perceived Similarity." Journal of Social and Personal Relationships, 2008, vol. 25, no. 6, pp. 889 to 922. https://doi.org/10.1177/0265407508096700 Type: Meta-analysis. Status: Verified 2026-09-22 against the Crossref record.

R6. Luo and Klohnen (2005)

Luo, Shanhong and Eva C. Klohnen. "Assortative Mating and Marital Quality in Newlyweds: A Couple-Centered Approach." Journal of Personality and Social Psychology, 2005, vol. 88, no. 2, pp. 304 to 326. https://doi.org/10.1037/0022-3514.88.2.304 Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record.

R7. Joel, Eastwick and colleagues (2020)

Joel, Samantha, Paul W. Eastwick and colleagues. "Machine Learning Uncovers the Most Robust Self-Report Predictors of Relationship Quality Across 43 Longitudinal Couples Studies." Proceedings of the National Academy of Sciences, 2020, vol. 117, no. 32, pp. 19061 to 19071. https://doi.org/10.1073/pnas.1917036117 Type: Peer-reviewed study (large multi-study analysis). Status: Verified 2026-09-22 against the Crossref record.

R8. Sternberg (1986)

Sternberg, Robert J. "A Triangular Theory of Love." Psychological Review, 1986, vol. 93, no. 2, pp. 119 to 135. https://doi.org/10.1037/0033-295x.93.2.119 Type: Peer-reviewed theory paper. Status: Verified 2026-09-22 against the Crossref record.

R9. Sternberg (1997)

Sternberg, Robert J. "Construct Validation of a Triangular Love Scale." European Journal of Social Psychology, 1997, vol. 27, no. 3, pp. 313 to 335. https://doi.org/10.1002/(sici)1099-0992(199705)27:3%3C313::aid-ejsp824%3E3.0.co;2-4 Type: Peer-reviewed study. Status: Verified 2026-09-22 against the Crossref record.

R10. Hendrick and Hendrick (1986)

Hendrick, Clyde and Susan Hendrick. "A Theory and Method of Love." Journal of Personality and Social Psychology, 1986, vol. 50, no. 2, pp. 392 to 402. https://doi.org/10.1037/0022-3514.50.2.392 Type: Peer-reviewed study (the Love Attitudes Scale, after Lee's love styles). Status: Verified 2026-09-22 against the Crossref record.

R11. Lee (1973)

Lee, John Alan. Colours of Love: An Exploration of the Ways of Loving. Toronto: New Press, 1973.

Type: Primary book (love styles typology). Status: Verified 2026-09-22 against the Open Library catalogue record.

Evidence status: Decades of research associate relationship stability with how couples handle conflict (Gottman's work on criticism, contempt, defensiveness and stonewalling), with each partner's own commitment and appreciation, and, more weakly, with similarity in values and attitudes. No questionnaire, including ours, predicts an individual couple's future; the couple compatibility quiz shows how you answered on nine dimensions drawn from this research.

Used on: Couple Compatibility Quiz (Relationship Compatibility Test), What Compatibility Means in a Relationship.

C. Attachment

T1. Hazan and Shaver (1987)

Hazan, Cindy and Phillip Shaver. "Romantic Love Conceptualized as an Attachment Process." Journal of Personality and Social Psychology, 1987, vol. 52, no. 3, pp. 511 to 524. https://doi.org/10.1037/0022-3514.52.3.511 Type: Peer-reviewed study (adult attachment applied to romantic love). Status: Verified 2026-09-22 against the Crossref record.

T2. Bowlby (1969)

Bowlby, John. Attachment and Loss, Volume 1: Attachment. New York: Basic Books, 1969.

Type: Primary book (attachment theory). Status: Verified 2026-09-22 against the Open Library catalogue record.

T3. Ainsworth, Blehar, Waters and Wall (1978)

Ainsworth, Mary D. Salter, Mary C. Blehar, Everett Waters and Sally Wall. Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale, NJ: Lawrence Erlbaum Associates, 1978.

Type: Primary book (the original attachment classifications). Status: Verified 2026-09-22 against the Open Library catalogue record.

T4. Bartholomew and Horowitz (1991)

Bartholomew, Kim and Leonard M. Horowitz. "Attachment Styles Among Young Adults: A Test of a Four-Category Model." Journal of Personality and Social Psychology, 1991, vol. 61, no. 2, pp. 226 to 244. https://doi.org/10.1037/0022-3514.61.2.226 Type: Peer-reviewed study (the four adult styles). Status: Verified 2026-09-22 against the Crossref record.

T5. Fraley, Waller and Brennan (2000)

Fraley, R. Chris, Niels G. Waller and Kelly A. Brennan. "An Item Response Theory Analysis of Self-Report Measures of Adult Attachment." Journal of Personality and Social Psychology, 2000, vol. 78, no. 2, pp. 350 to 365. https://doi.org/10.1037/0022-3514.78.2.350 Type: Peer-reviewed study (the ECR-R measure). Status: Verified 2026-09-22 against the Crossref record.

Evidence status: Adult attachment is a well-studied framework with validated measures. Attachment styles describe patterns, not fixed types, and they can change. This site describes the framework and its pairings as the literature discusses them; it does not offer an attachment quiz, because the validated measures are research instruments and a shortened version would not be one.

Used on: Attachment Style Compatibility.

D. Western astrology: conventions and evidence

Two kinds of source: the tradition's own reference works, cited to describe the tradition faithfully, and the empirical tests, cited to state honestly what the evidence shows.

Z1. Ptolemy, Tetrabiblos

Ptolemy, Claudius. Tetrabiblos. Translated by F. E. Robbins. Loeb Classical Library 435. Cambridge, MA: Harvard University Press, 1940. (Second century CE original.)

Type: Classical reference (elements, triplicities, aspects). Status: Verified 2026-09-22 against the Open Library catalogue record.

Z2. Sakoian and Acker (1976)

Sakoian, Frances and Louis S. Acker. The Astrology of Human Relationships. New York: Harper and Row, 1976.

Type: Practitioner reference (synastry). Status: Verified 2026-09-22 against the Open Library catalogue record.

Z3. Hand (1981)

Hand, Robert. Horoscope Symbols. Atglen, PA: Whitford Press, 1981.

Type: Practitioner reference (aspects, planets, signs). Status: Verified 2026-09-22 against the Open Library catalogue record.

Z4. Arroyo (1979)

Arroyo, Stephen. Relationships and Life Cycles: Modern Dimensions of Astrology. Sebastopol, CA: CRCS Publications, 1979.

Type: Practitioner reference (element compatibility). Status: Verified 2026-09-22 against the Open Library catalogue record.

Z5. Carlson (1985)

Carlson, Shawn. "A Double-Blind Test of Astrology." Nature, 1985, vol. 318, pp. 419 to 425. https://doi.org/10.1038/318419a0 Type: Peer-reviewed empirical test. Status: Verified 2026-09-22 against the Crossref record.

Evidence status: Western astrology is a tradition with a long history and a real, learnable set of rules, which these pages describe as its practitioners hold them. The best-known controlled test, Carlson's double-blind study in Nature (Z5), found that astrologers could not match birth charts to personality profiles better than chance, and no controlled test we have been able to open shows that birth dates or sun signs predict personality or how two people get on. We label it a tradition and treat it as one.

Used on: Zodiac Compatibility, Zodiac Friendship Compatibility.

E. Vedic astrology and kundli matching

V2. Raman, Muhurtha

Raman, Bangalore Venkata. Muhurtha (Electional Astrology). Bangalore: IBH Prakashana, 1979 (many editions).

Type: Practitioner reference (marriage matching, kootas). Status: Verified 2026-09-22 against the Open Library catalogue record.

Evidence status: Kundli matching (guna milan) is a Vedic tradition that scores a marriage match out of 36 points across eight categories. The page describes the system as the tradition states it. There is no evidence that it predicts marital outcomes, and the page says so.

Used on: Kundli Matching (Kundali Matching) Explained.

F. Chinese zodiac

C1. Lau (1979)

Lau, Theodora. The Handbook of Chinese Horoscopes. New York: Harper and Row, 1979 (later editions with Laura Lau).

Type: Practitioner reference (the twelve animals, trines, compatibility). Status: Verified 2026-09-22 against the Open Library catalogue record.

C2. Walters (1987)

Walters, Derek. Chinese Astrology: The Most Comprehensive Study of the Subject Ever Published in the English Language. Wellingborough: Aquarian Press, 1987.

Type: Reference (the calendar, the animals, the trine and clash conventions). Status: Verified 2026-09-22 against the Open Library catalogue record.

Evidence status: The Chinese zodiac is a tradition built on the lunisolar calendar. The trine, harmony and clash pairings are conventions of that tradition, described here as the reference works state them, and are not evidence about any two people.

Used on: Chinese Zodiac Compatibility.

G. Numerology

N1. Balliett (1908)

Balliett, L. Dow. The Philosophy of Numbers: Their Tone and Colors. Atlantic City, NJ: L. N. Fowler, 1908.

Type: Historical primary source (the modern "Pythagorean" letter-number system). Status: Verified 2026-09-22 against the Open Library catalogue record.

N2. Decoz and Monte (1994)

Decoz, Hans with Tom Monte. Numerology: Key to Your Inner Self. Garden City Park, NY: Avery, 1994; revised edition New York: Perigee, 2001.

Type: Practitioner reference (life path calculation, master numbers, compatibility). Status: Verified 2026-09-22 against the Open Library catalogue record.

N3. Dudley (1997)

Dudley, Underwood. Numerology: Or, What Pythagoras Wrought. Washington, DC: Mathematical Association of America, 1997.

Type: Scholarly history and critique. Status: Verified 2026-09-22 against the Open Library catalogue record.

Evidence status: Pythagorean numerology is a modern tradition (its letter-number system dates from the early twentieth century) with fixed, learnable rules, which these pages apply as the reference works state them. The grouping of life paths into 1-5-7, 2-4-8 and 3-6-9 is one popular reading, not a rule every numerologist uses, and the pair 4 with 8 is read both ways inside the tradition. There is no evidence that birth dates or names predict compatibility. We label it a tradition.

Used on: Numerology Compatibility Calculator.

H. FLAMES, the paper love games and playground folklore

No peer-reviewed source describes FLAMES specifically, and we could not find a documented origin for it. FLAMES and the two paper love games, TRUE LOVE and LOVES, are children's counting-out games of the same family as MASH and the cootie catcher, documented in the folklore literature, and the exact FLAMES procedure is passed on by players (which is why variants exist).

One of the paper games has been studied. Johnston (2016) analyses the LOVES game, which counts the letters L, O, V, E and S in two names and keeps adding neighbouring numbers, and shows that the adding step does not always finish. For the TRUE LOVE game, two informal descriptions agree on the rule: add the TRUE counts, add the LOVE counts, and set the two totals side by side. No source that meets our standard describes it, and we say so instead of citing a weaker one. Our name calculator follows that TRUE LOVE rule.

F1. Opie and Opie (1959)

Opie, Iona and Peter Opie. The Lore and Language of Schoolchildren. Oxford: Clarendon Press, 1959.

Type: Folklore reference (counting-out rhymes, love divination games among British schoolchildren). Status: Verified 2026-09-22 against the Open Library catalogue record.

F2. Knapp and Knapp (1976)

Knapp, Mary and Herbert Knapp. One Potato, Two Potato: The Folklore of American Children. New York: W. W. Norton, 1976.

Type: Folklore reference (American playground games, fortune-telling games). Status: Verified 2026-09-22 against the Open Library catalogue record.

F3. Bronner (1988)

Bronner, Simon J. American Children's Folklore. Little Rock: August House, 1988.

Type: Folklore reference (fortune-telling games, MASH and relatives). Status: Verified 2026-09-22 against the Open Library catalogue record.

F4. Johnston (2016)

Johnston, Iain G. "Endless love: On the termination of a playground number game." arXiv:1602.03556, 2016. https://arxiv.org/abs/1602.03556. University of Birmingham news release, 16 February 2016.

Type: Mathematical study of the paper LOVES game. Status: Verified 2026-09-21 against the arXiv record.

Evidence status: FLAMES and the paper love games are counting games from the playground tradition of fortune-telling games. They have no origin we can document beyond that tradition, no author, and no meaning beyond the game. That is why they are labelled Game.

Used on: FLAMES Calculator, How to Do the Love Calculator on Paper.

I. Name-based calculators and love testers: history

H1. Nintendo Love Tester (1969)

Nintendo Co., Ltd. Love Tester (electronic toy), designed by Gunpei Yokoi, 1969.

Type: Product record (the origin of the "love tester" name in consumer products). Status: Verified 2026-09-22 against the product record (Nintendo, 1969, designed by Gunpei Yokoi).

Evidence status: Online love calculators are a web-era continuation of a much older novelty: electronic and coin-operated "love testers" that returned a verdict from a hand on a sensor. None measured anything. Ours does not either, and it says so.

Used on: Love Calculator by LoveCalculator.love.

Which guidance documents does the site follow?

The site follows five guidance and policy documents. They are not research; they are listed for transparency, because they govern how the site handles links, endorsements, children's privacy, ads and accessibility.

ID	Citation	Status
G1	Google Search Central. "Qualify your outbound links to Google" (the page describes rel="sponsored" and rel="ugc"; their introduction is the Search Central blog post of September 2019 that the page links to).	Verified 2026-09-22, page opened
G2	Federal Trade Commission. "Guides Concerning Use of Endorsements and Testimonials in Advertising" (16 CFR Part 255), as revised 26 July 2023 (88 FR 48102).	Verified 2026-09-22 against the Code of Federal Regulations text
G3	Federal Trade Commission. Children's Online Privacy Protection Rule (16 CFR Part 312), as amended 22 April 2025 (90 FR 16977).	Verified 2026-09-22 against the Code of Federal Regulations text
G4	Google AdSense Help. "AdSense policies: a beginner's guide" (support.google.com/adsense/answer/23921), which restates the Google Publisher Policies rule against content ads on interstitial pages and game interfaces.	Verified 2026-09-22, page opened (the draft cited it under the title "Google Publisher Policies"; the article's own title is now used)
G5	W3C. Web Content Accessibility Guidelines (WCAG) 2.2. W3C Recommendation, first published 2023, edition of 12 December 2024.	Verified 2026-09-22, page opened

Which sources were considered and not used?

Four kinds of source were considered and not used, each for a stated reason:

Any content-farm or "top 10 love calculator" page: not a source for anything.
The 5lovelanguages.com quiz and site: a commercial product page, not a source; and the brand name is trademarked. The book (L1) is the source.
Astrology marketplaces' "compatibility" articles: commercial pages with no method shown.
Social-network posts about the moon phase test or the TikTok compatibility test: the pages describe the format from the videos themselves and cite nothing, because there is nothing citable; the page says the format is a game.