Biases

Biases in tests of treatments are those influences and factors that can lead to conclusions about treatment effects that are systematically different from the truth.

863 RECORDS
124 ARTICLES
1 BLOG

The need to address treatment uncertainties

Principles of Testing

Treatment comparisons are essential

Treatment comparisons must be fair

Biases

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The play of chance

Bringing it all together for the benefit of patients and the public

James Lind LibraryIllustrating the development of fair tests of treatments in health care

Biases

Biases in tests of treatments are those influences and factors that can lead to conclusions about treatment effects that are systematically different from the truth.

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863 RECORDS

124 ARTICLES

1 BLOG

Bacon F (1626) The New Atlantis. Republished in: Rawley W (1685). Sylva Sylvarum: or a natural history in ten centuries. Written by the Right Honorable Francis, Lord Verulam, Viscount St. Albans. Eleventh edition. London: Printed for B Griffin.

Bacon F (1645) Franc Baconis de Verulamio / Summi Angliae Cancellarii /Novum organum scientiarum. Lugd. Bat: apud Adrianum Wiingaerde, et Franciscum Moiardum. Aphorism XLVI (pages 45-46).

Starkey G (1657) Natures explication and Helmont’s vindication…Or A short and sure way to a long and sound life. London: printed by E. Cotes for Thomas Alsop at the two Sugar-loaves over against St. Antholins Church at the lower end of Watling Street.

Boyle R (1661) In defense of Experimental Essays. In: Certain Physiological Essays, written at distant times, and on several occasions pp 4-5. London: Printed for Henry Herringman at the Anchor in the Lower walk in the New-Exchange.

Wiseman R (1676) Eight chirugical treatises. London: R Royston, p 123.

Massey I (1723) A short and plain account of inoculation. With some remarks on the main argument made use of to recommend that practice, by Mr. Maitland and others. To which is added, a letter to the learned James Jurin, M.D.R.S. Secr. Col. Reg. Med. Lond. Soc. London: W. Meadows.

Lind J (1753) A treatise of the scurvy. In three parts. Containing an inquiry into the nature, causes and cure, of that disease. Together with a critical and chronological view of what has been published on the subject. Edinburgh: Printed by Sands, Murray and Cochran for A Kincaid and A Donaldson.

Gregory J (1772) Lectures on the duties and qualifications of a physician. London: Strahan and Cadell. (new ed.) Edinburgh: Creech.

Haygarth J (1784) An inquiry into how to prevent smallpox. Chester and London.

Commission Royale. Bailly A (1784) Rapport des commissaires chargés par le Roi, de l'examen du magnétisme animale [Report of the Comissioners required by the King to examine animal magnetism]. Imprimé par ordre du Roi. Paris: A Paris, de L'Imprimerie Royale.

Withering W (1785) An account of the foxglove and some of its medical uses: with practical remarks on dropsy and other diseases. London: J and J Robinson.

Parry CH (1786) Experiments relative to the medical effects of Turkey Rhubarb, and of the English Rhubarbs, No. I and No. II made on patients of the Pauper Charity. Letters and Papers of the Bath Society 11:431-453.

Fowler T (1786) Medical reports of the effects of arsenic in the cure of agues, remitting fevers and periodic headachs. London: J Johnson, pp 105-107.

Sims RC (1791) Letter VI. Letters and Papers of the Bath Society III: 486-487.

Haygarth J (1793) Sketch of a plan to exterminate the casual smallpox from Great Britain; and to introduce general inoculation. London: J Johnson

Currie J (1797) Medical reports on the effects of water, cold and warm, as a remedy in fever, and febrile diseases. Liverpool and London: M’Creery and Cadell.

Haygarth J (1800) Of the imagination, as a cause and as a cure of disorders of the body: exemplified by fictitious tractors, and epidemical convulsions. Bath: R. Crutwell.

de Villalba J (1802) Epidemiología Española. Madrid: D Fermin Villalpando.

Lesassier Hamilton A (1816) Dissertatio Medica Inauguralis De Synocho Castrensi [Inaugural medical dissertation on camp fever]. Edinburgh: J Ballantyne.

Löhner G, on behalf of a Society of truth-loving men (1835) Die Homoöopathischen Kochsalzversuche zu Nürnberg [The homeopathic salt trials in Nurnberg]. Nürnberg in März.

Carlisle A (1839) On the production of representations of objects by the action of light. Mechanics Journal p 329.

Tessier JP (1852) De la médication homoeopathique [On homoeopathic medication]. Paris: JB Ballière.

Balfour TG (1854) Quoted in West C. Lectures on the Diseases of Infancy and Childhood. London, Longman, Brown, Green and Longmans, p 600.

Thompson T (1859) Observations on the administration of ozonized oils. Medical and Chirurgical Transactions 42:349-360.

Holmes OW (1861) Currents and countercurrents in medical science with other addresses and essays. Boston: Ticknor and Fields, 1861.

Semmelweis I (1861) Die Aetiologie, der Begriff und die Prophylaxis des Kindbettfiebers. [The etiology, concept, and prophylaxis of childbed fever]. Budapest and Vienna; Hartleben.

Bennett JH (1865) The restorative treatment of pneumonia. Edinburgh, AC Black.

Wanscher O (1877) Om Diphteritis og Croup - særligt med hensyn til Tracheostomien ved samme. [On diphtheria and croup - especially regarding tracheostomy in this condition]. Disputats [Thesis]. Jacob Lund: Kjøbenhavn, p 67-68.

Keith T (1878) Results of ovariotomy before and after antiseptics. BMJ 2;590-593. doi:10.1136/bmj.2.929.590.

Hill B (1879) Clinical lectures on stricture of the urethra. BMJ 2:883-886.

Storke EF, Martin R, Rosenkrans EM, Ford J, Schloemilch A, McDermott GC, Carlson OW (1880) Final report of the Milwaukee test of the thirtieth dilution. Homoeopathic Times 7:12/280-1.

Pasteur L (1881) Compte rendu sommaire des expériences rates á Pouilly-le-Fort, prés Melun, sur la vaccination charbonneuse [A summary account of experiences at Pouilly-le-Fort, near Mélun, on anthrax vaccination]. Comptes rendus de l'Académie des Sciences 92: 1378-1383.

Champneys FH (1881) On artificial respiration in still born children. The amount of ventilation secured by different methods. An experimental enquiry. Medical and Chirurgical Transactions 64 :41-86.

Cook County Board of Commissioners (1882) Proceedings, 1881-1882. Chicago, Illinois, 222-223.

Reverdin J-L, Reverdin A (1883) Note sur vingt-deux opérations de goitre, avec 3 pl. photographiques [Note on twenty two operations on goitre. Continuation and conclusion]. Revue Médicale de la Suisse Romande 3:169-198, 233-278, 309-364.

Kocher T (1883) Ueber Kropfexstirpation und ihre Folgen [On goitre removal, and its consequences]. Archiv für Klinische Chirurgie 29:254-337.

Rayleigh, The Lord (1885) Address by the Rt. Hon. Lord Rayleigh. In: Report of the fifty-fourth meeting of the British Association for the Advancement of Science; held at Montreal in August and September 1884. London: John Murray: 3-23.

Hartridge G (1886) Tobacco amblyopia. BMJ 1:200.

Fry HD (1887) The value of the antiseptic method in obstetric practice and its application to the forceps operation. JAMA 8:388-390.

Boxall, cited in Williams J (1888) On the effect of ergot on the involution of the uterus. BMJ 1:229.

Stuart W (1889) A remarkable case of morphine addiction. BMJ 1:1051-52.

Phillips J (1890) On the analgesic value of antipyrin intra - and post - partum. Lancet 2:605-607.

Behring EA, Boer NN, Kossel H (1893) Zur Behandlung diphtheriekranker Menschen mit Diphtherieheilserum [On the treatment of diphtheria patients with curative diphtheria serum]. Deutsche Medicinische Wochenschrift 17:389-39.

Roux E, Martin L, Chaillou A (1894) Trois cent cas de diphthérie traité par le serum antidiphthérique. Annales de l’Institut Pasteur 8:640-661.

Webster Fox L (1894) Immediate capsulotomy following the removal of cataract. JAMA 22:837-39.

Priestley J (1895) On the value of eucalyptus oil as a disinfectant in scarlet fever. Lancet 1:861-863.

Pregl F (1896) Zwei weitere ergographische Versuchsreihen über die Wirkung orchistischen Extraktes [Two further ergographic experimental series on the effects of testicular extracts]. Archiv für die gesamte Physiologie 62:379-399.

Winters JE (1896) Clinical observations upon the use of antitoxin in diphtheria: A report of personal investigation of this treatment in the principal fever hospitals of Europe during the summer of 1895. Medical Record 49:877-893.

Brown EH (1896) Cholera and its treatment by preventive inoculation in the Darbhanga Jail. Indian Medical Gazette, July, 247-250.

Vorderman AG (1897) Onderzoek naar het verband tusschen den aard der rijstvoeding in de gevangenissen op Java en Madoera en het voorkomen van beri-beri onder de geïnterneerden. Batavia: Jav. Boekh. & Drukkerij.

Fibiger J (1898) Om serumbehandling af difteri [On treatment of diphtheria with serum]. Hospitalstidende 6:309-325.

Langton J (1899) A discussion on the treatment of hernia in children. BMJ 2:470-472.

Clemow (1899) Yersin serum treatment of plague. BMJ 1:48.

Anonymous (1899) Echoes and news: the chlorine treatment of diphtheria. Medical News 74:403.

Williams FH (1899) Scarlatina. Reports of societies. Boston Medical And Surgical Journal 141:348.

Cotton FJ (1899) The Present Status of the Antistreptococcic Serum. New England Journal of Medicine 140:105-109. DOI: 10.1056/NEJM189902021400501

Maitland CB (1900) Methylene blue in malarial fever. BMJ 2:532-533.

Celli A (1900) The new prophylaxis against malaria in Lazio. Lancet 156; 4031:1603-1606.

Park WH (1900) The quantity of diphtheria antitoxin required in the treatment of diphtheria. Archives of Paediatrics 17:823-827.

Celli A (1900) La nuova profilassi della malaria nel Lazio [The new prophylaxis against malaria in Lazio]. Supplemento al Policlinico 6:1601-1606.

Haffkine WM (1900) On preventive inoculation. Proceedings of the Royal Society of London 65:252-271.

Park WH (1900) Use of diphtheria antitoxin in the treatment and prevention of diphtheria. JAMA 34: 902-904.

Choksy NH (1900) Professor Lustig’s plague serum. Lancet 2:291-292.

Lustig A, Galeotti G (1901) The prophylactic and curative treatment of plague. BMJ 1:206-208.

Choksy NH (1901) Plague treatment with Lustig’s serum. Indian Medical Gazette 36:154–155.

Indian Plague Commission (1902) Serum therapeutics. Investigations conducted by the commissioners. BMJ 1:1159-1160.

Fehling H (1903) Zur Prophylaxe und Therapie des Puerperalfiebers [On the prophylaxis and treatment of puerperal fever]. Muenchener Medizinische Wochenschrift, 18 Aug.

Waters EE (1903) Malaria as seen in the Andamans penal settlement. Lancet 1:1657-62.

Polverini G (1903) Serumtherapie gegen Beulenpest Muenchener Medizinische Wochenschrift 50:649-651.

Celli A (1903) La malaria in Italia durante il 1902. Parte II: Profilassi della malaria. [Malaria in Italy in 1902. Part II: Prophylaxis of Malaria]. Annali di Igiene Sperimentale 13:322-343.

Cushny AR, Peebles AR (1905) The action of optical isomers. II. Hyoscines. J Physiology 32:501-510.

Cousin M (1905) Des éruptions consecutives aux injections de sérum antidiphthérique et de leur traitement prophylactique par l’ingestion de clorure de calcium. Thèse pour le Doctorat en médicine. Paris : Jules Rousset, 36-44.

Goldberger J (1907) Typhoid "bacillus carriers". In: Rosenau MJ, Lumsden LL, Kastle JH. Report on the origin and prevalence of typhoid fever in the District of Columbia. Hygienic Laboratory, Bulletin No 35, pp 167-174.

James Lind Library
Illustrating the development of fair tests of treatments in health care

Bacon F (1626)
The New Atlantis. Republished in: Rawley W (1685). Sylva Sylvarum: or a natural history in ten centuries. Written by the Right Honorable Francis, Lord Verulam, Viscount St. Albans. Eleventh edition. London: Printed for B Griffin.

Bacon F (1645)
Franc Baconis de Verulamio / Summi Angliae Cancellarii /Novum organum scientiarum. Lugd. Bat: apud Adrianum Wiingaerde, et Franciscum Moiardum. Aphorism XLVI (pages 45-46).

Starkey G (1657)
Natures explication and Helmont’s vindication…Or A short and sure way to a long and sound life. London: printed by E. Cotes for Thomas Alsop at the two Sugar-loaves over against St. Antholins Church at the lower end of Watling Street.

Boyle R (1661)
In defense of Experimental Essays. In: Certain Physiological Essays, written at distant times, and on several occasions pp 4-5. London: Printed for Henry Herringman at the Anchor in the Lower walk in the New-Exchange.

Wiseman R (1676)
Eight chirugical treatises. London: R Royston, p 123.

Massey I (1723)
A short and plain account of inoculation. With some remarks on the main argument made use of to recommend that practice, by Mr. Maitland and others. To which is added, a letter to the learned James Jurin, M.D.R.S. Secr. Col. Reg. Med. Lond. Soc. London: W. Meadows.

Lind J (1753)
A treatise of the scurvy. In three parts. Containing an inquiry into the nature, causes and cure, of that disease. Together with a critical and chronological view of what has been published on the subject. Edinburgh: Printed by Sands, Murray and Cochran for A Kincaid and A Donaldson.

Gregory J (1772)
Lectures on the duties and qualifications of a physician. London: Strahan and Cadell. (new ed.) Edinburgh: Creech.

Haygarth J (1784)
An inquiry into how to prevent smallpox. Chester and London.

Commission Royale. Bailly A (1784)
Rapport des commissaires chargés par le Roi, de l'examen du magnétisme animale [Report of the Comissioners required by the King to examine animal magnetism]. Imprimé par ordre du Roi. Paris: A Paris, de L'Imprimerie Royale.

Withering W (1785)
An account of the foxglove and some of its medical uses: with practical remarks on dropsy and other diseases. London: J and J Robinson.

Parry CH (1786)
Experiments relative to the medical effects of Turkey Rhubarb, and of the English Rhubarbs, No. I and No. II made on patients of the Pauper Charity. Letters and Papers of the Bath Society 11:431-453.

Fowler T (1786)
Medical reports of the effects of arsenic in the cure of agues, remitting fevers and periodic headachs. London: J Johnson, pp 105-107.

Sims RC (1791)
Letter VI. Letters and Papers of the Bath Society III: 486-487.

Haygarth J (1793)
Sketch of a plan to exterminate the casual smallpox from Great Britain; and to introduce general inoculation. London: J Johnson

Currie J (1797)
Medical reports on the effects of water, cold and warm, as a remedy in fever, and febrile diseases. Liverpool and London: M’Creery and Cadell.

Haygarth J (1800)
Of the imagination, as a cause and as a cure of disorders of the body: exemplified by fictitious tractors, and epidemical convulsions. Bath: R. Crutwell.

de Villalba J (1802)
Epidemiología Española. Madrid: D Fermin Villalpando.

Lesassier Hamilton A (1816)
Dissertatio Medica Inauguralis De Synocho Castrensi [Inaugural medical dissertation on camp fever]. Edinburgh: J Ballantyne.

Löhner G, on behalf of a Society of truth-loving men (1835)
Die Homoöopathischen Kochsalzversuche zu Nürnberg [The homeopathic salt trials in Nurnberg]. Nürnberg in März.

Carlisle A (1839)
On the production of representations of objects by the action of light. Mechanics Journal p 329.

Tessier JP (1852)
De la médication homoeopathique [On homoeopathic medication]. Paris: JB Ballière.

Balfour TG (1854)
Quoted in West C. Lectures on the Diseases of Infancy and Childhood. London, Longman, Brown, Green and Longmans, p 600.

Thompson T (1859)
Observations on the administration of ozonized oils. Medical and Chirurgical Transactions 42:349-360.

Holmes OW (1861)
Currents and countercurrents in medical science with other addresses and essays. Boston: Ticknor and Fields, 1861.

Semmelweis I (1861)
Die Aetiologie, der Begriff und die Prophylaxis des Kindbettfiebers. [The etiology, concept, and prophylaxis of childbed fever]. Budapest and Vienna; Hartleben.

Bennett JH (1865)
The restorative treatment of pneumonia. Edinburgh, AC Black.

Wanscher O (1877)
Om Diphteritis og Croup - særligt med hensyn til Tracheostomien ved samme. [On diphtheria and croup - especially regarding tracheostomy in this condition]. Disputats [Thesis]. Jacob Lund: Kjøbenhavn, p 67-68.

Keith T (1878)
Results of ovariotomy before and after antiseptics. BMJ 2;590-593. doi:10.1136/bmj.2.929.590.

Hill B (1879)
Clinical lectures on stricture of the urethra. BMJ 2:883-886.

Storke EF, Martin R, Rosenkrans EM, Ford J, Schloemilch A, McDermott GC, Carlson OW (1880)
Final report of the Milwaukee test of the thirtieth dilution. Homoeopathic Times 7:12/280-1.

Pasteur L (1881)
Compte rendu sommaire des expériences rates á Pouilly-le-Fort, prés Melun, sur la vaccination charbonneuse [A summary account of experiences at Pouilly-le-Fort, near Mélun, on anthrax vaccination]. Comptes rendus de l'Académie des Sciences 92: 1378-1383.

Champneys FH (1881)
On artificial respiration in still born children. The amount of ventilation secured by different methods. An experimental enquiry. Medical and Chirurgical Transactions 64 :41-86.

Cook County Board of Commissioners (1882)
Proceedings, 1881-1882. Chicago, Illinois, 222-223.

Reverdin J-L, Reverdin A (1883)
Note sur vingt-deux opérations de goitre, avec 3 pl. photographiques [Note on twenty two operations on goitre. Continuation and conclusion]. Revue Médicale de la Suisse Romande 3:169-198, 233-278, 309-364.

Kocher T (1883)
Ueber Kropfexstirpation und ihre Folgen [On goitre removal, and its consequences]. Archiv für Klinische Chirurgie 29:254-337.

Rayleigh, The Lord (1885)
Address by the Rt. Hon. Lord Rayleigh. In: Report of the fifty-fourth meeting of the British Association for the Advancement of Science; held at Montreal in August and September 1884. London: John Murray: 3-23.

Hartridge G (1886)
Tobacco amblyopia. BMJ 1:200.

Fry HD (1887)
The value of the antiseptic method in obstetric practice and its application to the forceps operation. JAMA 8:388-390.

Boxall, cited in Williams J (1888)
On the effect of ergot on the involution of the uterus. BMJ 1:229.

Stuart W (1889)
A remarkable case of morphine addiction. BMJ 1:1051-52.

Phillips J (1890)
On the analgesic value of antipyrin intra - and post - partum. Lancet 2:605-607.

Behring EA, Boer NN, Kossel H (1893)
Zur Behandlung diphtheriekranker Menschen mit Diphtherieheilserum [On the treatment of diphtheria patients with curative diphtheria serum]. Deutsche Medicinische Wochenschrift 17:389-39.

Roux E, Martin L, Chaillou A (1894)
Trois cent cas de diphthérie traité par le serum antidiphthérique. Annales de l’Institut Pasteur 8:640-661.

Webster Fox L (1894)
Immediate capsulotomy following the removal of cataract. JAMA 22:837-39.

Priestley J (1895)
On the value of eucalyptus oil as a disinfectant in scarlet fever. Lancet 1:861-863.

Pregl F (1896)
Zwei weitere ergographische Versuchsreihen über die Wirkung orchistischen Extraktes [Two further ergographic experimental series on the effects of testicular extracts]. Archiv für die gesamte Physiologie 62:379-399.

Winters JE (1896)
Clinical observations upon the use of antitoxin in diphtheria: A report of personal investigation of this treatment in the principal fever hospitals of Europe during the summer of 1895. Medical Record 49:877-893.

Brown EH (1896)
Cholera and its treatment by preventive inoculation in the Darbhanga Jail. Indian Medical Gazette, July, 247-250.

Vorderman AG (1897)
Onderzoek naar het verband tusschen den aard der rijstvoeding in de gevangenissen op Java en Madoera en het voorkomen van beri-beri onder de geïnterneerden. Batavia: Jav. Boekh. & Drukkerij.

Fibiger J (1898)
Om serumbehandling af difteri [On treatment of diphtheria with serum]. Hospitalstidende 6:309-325.

Langton J (1899)
A discussion on the treatment of hernia in children. BMJ 2:470-472.

Clemow (1899)
Yersin serum treatment of plague. BMJ 1:48.

Anonymous (1899)
Echoes and news: the chlorine treatment of diphtheria. Medical News 74:403.

Williams FH (1899)
Scarlatina. Reports of societies. Boston Medical And Surgical Journal 141:348.

Cotton FJ (1899)
The Present Status of the Antistreptococcic Serum. New England Journal of Medicine 140:105-109. DOI: 10.1056/NEJM189902021400501

Maitland CB (1900)
Methylene blue in malarial fever. BMJ 2:532-533.

Celli A (1900)
The new prophylaxis against malaria in Lazio. Lancet 156; 4031:1603-1606.

Park WH (1900)
The quantity of diphtheria antitoxin required in the treatment of diphtheria. Archives of Paediatrics 17:823-827.

Celli A (1900)
La nuova profilassi della malaria nel Lazio [The new prophylaxis against malaria in Lazio]. Supplemento al Policlinico 6:1601-1606.

Haffkine WM (1900)
On preventive inoculation. Proceedings of the Royal Society of London 65:252-271.

Park WH (1900)
Use of diphtheria antitoxin in the treatment and prevention of diphtheria. JAMA 34: 902-904.

Choksy NH (1900)
Professor Lustig’s plague serum. Lancet 2:291-292.

Lustig A, Galeotti G (1901)
The prophylactic and curative treatment of plague. BMJ 1:206-208.

Choksy NH (1901)
Plague treatment with Lustig’s serum. Indian Medical Gazette 36:154–155.

Indian Plague Commission (1902)
Serum therapeutics. Investigations conducted by the commissioners. BMJ 1:1159-1160.

Fehling H (1903)
Zur Prophylaxe und Therapie des Puerperalfiebers [On the prophylaxis and treatment of puerperal fever]. Muenchener Medizinische Wochenschrift, 18 Aug.

Waters EE (1903)
Malaria as seen in the Andamans penal settlement. Lancet 1:1657-62.

Polverini G (1903)
Serumtherapie gegen Beulenpest Muenchener Medizinische Wochenschrift 50:649-651.

Celli A (1903)
La malaria in Italia durante il 1902. Parte II: Profilassi della malaria. [Malaria in Italy in 1902. Part II: Prophylaxis of Malaria]. Annali di Igiene Sperimentale 13:322-343.

Cushny AR, Peebles AR (1905)
The action of optical isomers. II. Hyoscines. J Physiology 32:501-510.

Cousin M (1905)
Des éruptions consecutives aux injections de sérum antidiphthérique et de leur traitement prophylactique par l’ingestion de clorure de calcium. Thèse pour le Doctorat en médicine. Paris : Jules Rousset, 36-44.

Goldberger J (1907)
Typhoid "bacillus carriers". In: Rosenau MJ, Lumsden LL, Kastle JH. Report on the origin and prevalence of typhoid fever in the District of Columbia. Hygienic Laboratory, Bulletin No 35, pp 167-174.

Drake DJ (1907)
The treatment of dysentery by yellow santonine. Journal of Tropical Medicine and Hygiene 10:351-352.

Fletcher W (1907)
Rice and beri-beri: preliminary report on an experiment conducted in the Kuala Lumpur Insane Asylum. Lancet 1:1776-1779.

Rivers WHR (1908)
The influence of alcohol and other drugs on fatigue. London: Edward Arnold.

Gewin J (1908)
Chlorkalzium gegen die Serumkrankheit [Calcium chloride against serum sickness]. Muenchener Medizinische Wochenshcrift 50:2670-2671.

Choksy NH (1908)
On recent progress in serum-therapy of plague. BMJ 1:1282-1284.

Anonymous (1908)
Alcohol in the treatment of pneumonia and enteric fever. Lancet 157:442.