H&a Revolver Serial Number Lookup

The Heritage Model Number Lookup System will help you find detailed information about your Heritage Gun. Enter the serial number (no spaces) of your firearm. Gun data,gun-data, gun serial numbers, gun manufacturing data, gun information,gun schematics,historic guns, historic gun data,historic firearms,antique gun. As of 1875 H&A made several lines of revolvers exclusively for Merwin, Hulbert & Co. The XL series however, with a double action feature and with a trigger guard. Scott Revolver Rifle Sterling Thames Arms Company? Tower's Police Safety Universal XL. Approximate Serial Number Range of the XL No. 8, including the Navy and Police.

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H&R 1871, LLC
Subsidiary
Industry	Firearms
Founded	1871
Headquarters	Ilion, N.Y. (manuf.) & Madison, N.C., (admin.)
Key people	Nathan Harrington, William Augustus Richardson, George F. Brooks
Products	Single-shot, pump-action, and semi-auto shotguns. Single-shot rifles.
Website	H&R Website

H&R 1871, LLC (Harrington & Richardson) is a manufacturer of firearms under the Harrington & Richardson and New England Firearms trademarks. H&R is a subsidiary of the Remington Outdoor Company. H&R ceased production February 27, 2015.

6Products

History[edit]

The original H&R firm was in business for over a century from 1871 to 1986.^[1]

Frank Wesson, brother of Daniel B. Wesson who co-founded Smith & Wesson, started a firearms manufacturing firm in 1859, sharing an early patent with Nathan Harrington. Wesson produced two trigger rifles and spur trigger pistols and pocket rifles/shotguns popular for short length holster models such as the discontinued topper compact pocket shotguns. He started a brief partnership in 1871 with his nephew Gilbert Henderson Harrington, as Wesson & Harrington, until Harrington bought him out in 1874.

In 1875 Harrington and another former Wesson employee, William Augustus Richardson, formed the new Harrington & Richardson Company. In 1888 the firm was incorporated as The Harrington & Richardson Arms Company. Their original capital investment was $75,000. Harrington was president, Richardson was treasurer, and George F. Brooks was secretary. After the deaths of Harrington and Richardson in 1897, Brooks became the manager and the company was held by heirs Edwin C. Harrington (Gilbert Harrington's son) and Mary A. Richardson (William Richardson's wife).

In 1894 the company opened a new facility on Park Avenue in Worcester, Massachusetts. The factory was expanded again after a few years. The firearms produced during this period are great values to collectors, selling at low to moderate prices. Original rifles and shotguns from these dates are scarce because of their limited production and discontinued parts.

In 1950 the company opened a new facility on Cockburn street in Drummondville, Québec, Canada.

In the 1960s H&R was acquired by the Kidde corporation and run by the Rowe family. Warranty cards were sent to 'Industrial Rowe', Gardner, Massachusetts.^[2] The original H&R company went out of business in 1986, and the building was demolished.^[3]

A new company, H&R 1871, Inc., was formed in 1991 and started production of revolvers, single-shot rifles and shotguns using original H&R designs. H&R 1871, Inc. assets were subsequently sold to H&R 1871, LLC., a Connecticut LLC owned by Marlin Firearms Company in November 2000. H&R 1871, LLC. did not extend their product warranty to H&R guns made prior to the LLC's takeover.

Marlin, including all its H&R assets, was later acquired by Remington Arms Company in December, 2007. H&R 1871, LLC production was moved to Ilion, N.Y. (the site of Remington's original manufacturing plant) in late 2008, while their corporate offices are co-located with Remington Arms in Madison, N.C. (HR1871.com and Remington.com).^{[citation needed]} Remington, along with its Marlin and H&R subsidiaries, are now part of the Remington Outdoor Company. H&R 1871 production ceased 27 February 2015.

Locations[edit]

The Wesson & Harrington company was at 18 Manchester Street, Worcester, Mass., from 1871 until 1877.
The Harrington & Richardson company was located at 31 Hermon Street, Worcester, Mass., from 1877 until 1894.
William Richardson lived at 921 Main Street in Worcester.

Some of the other factory addresses that Harrington & Richardson has used:

Harrington & Richardson Arms Co., 243 Park Ave, Worcester, Mass.
Harrington & Richardson Arms Co., 320 Park Ave, Worcester, Mass.
Harrington & Richardson Arms Co., 439 Park Ave, Worcester, Mass.
Harrington & Richardson Arms Co., 484 Park Ave, Worcester, Mass.
H&R 1871, Inc., Industrial Rowe, Gardner, Mass.
H&R 1871, LLC., P.O. Box 1871, Madison, N.C. 27025 (corporate offices)
H&R 1871, LLC. 14 Hoefler Ave, Ilion, N.Y. 13357 (production facilities)

Military contributions[edit]

H&R built flare guns during World War I and a variety of firearms, including the Reising submachine gun, during World War II. H&R was granted a contract to produce the M1 rifle during the Korean War, but the first deliveries of the rifles were not made until after the armistice. H&R manufactured the M14 rifle during that rifle's production cycle (1959–1964). H&R also manufactured M16A1 rifles during the Vietnam War and is one of only four manufacturers (along with Colt, Fabrique Nationale, & GM Hydramatic Division) to have ever made an official M16 variant for the U.S. Military.^[1] Due to their relative scarcity, all H&R military weapons are considered highly desirable by collectors.

Miscellaneous[edit]

The firm was named sole North American licensee for England's Anson & Deely double-barrel hammerless shotgun.^[4]
In 1932, an H&R pistol was used to set a new U.S. pistol record and went on to become the most famous firearm of its kind—the U.S.R.A. single-shot target pistol. This pistol was so accurate that it was adopted by the U.S. Army Pistol Team.^[5]

Patents[edit]

Patent # 1984677:^[6] H&R also made handcuffs. Patented in 1934 by Harrington and Richardson.
Patent # 1572262^[7] (02/09/1926) issued to H&R.
Patent # 2388766^[8] (11/13/1945) issued to H&R.

Products[edit]

Revolvers[edit]

H&R Revolver of Top-Break design

H&R Revolver of Top-Break design with knife

The 3rd model of the .38 S&W H&R Hammerless Safety came out in 1909. Flat springs common to the first two models were replaced with coil wire.

Early break-action model with factory pearl grips.

H&R Sportsman (.22 LR nine-shot revolver 6-inch barrel – blued finish)
Manual Ejecting Model .32 S&W or .38 S&W cal., 5-shot (.32 cal.) or 6 -shot (.38 cal.), manual ejecting rod under barrel, hard rubber grip panels with Floral design, nickel finish, marked on top of barrel with company name and address only, 3¹⁄₄ in. barrel, modified American Double Action mechanism and frame. Mfg. 1885–1889.
Manual Ejecting Second Model .32 S&W or .38 S&W cal., 5- or 6-shot, new frame (same as Second Model Auto Ejecting), 3 1/4 in. barrel, hard rubber grips with target logo, nickel or blue finish, one patent date marking, very rare. Mfg. 1890 – disc.
Top-Break Auto Ejecting .32 S&W or .38 S&W cal., 5-shot (.38 cal.) or 6-shot cylinder, hard rubber grip panels with floral design, 3¹⁄₄ in. barrel, modified American Double Action mechanism and frame, nickel finish, First Variation marked on top of barrel with company name and address only and two guide rods for ejector (1885-1886), Second Variation patent date 10-4-87 marked on top of barrel along with company name and address, extractor does not have extra guide rods (1887-1889). Mfg. 1885-1889.
Top-Break Automatic Ejecting Model 1¹⁄₂ .32 S&W or .38 S&W cal., different double-action mechanism, trigger, trigger guard and hammer, 5-shot (.38 S&W cal.) or 6-shot (.32 S&W cal.), new frame, nickel or blue finish, hard rubber grips with target logo, 3¹⁄₄ in. barrel, marked with two patent date 10-04-87 and 12-25-88 (only revolver to use this date), rare. Mfg. 1889-1890
H&R Knife Pistol (.32, .38 manufactured in 1901)

H&R Vest-Pocket Self-Cocker (Early model)

H&R Vest-Pocket Self-Cocker (Later model)

H&R The American Double Action

H&R Double Action Safety Hammer

Model 1 .32 caliber 7-shot or .38 Caliber 5-shot, spur trigger single-action revolver, 3-inch octagonal barrel, fluted cylinder, flat frame, saw-handle square butt, plain walnut or black checkered rubber grips, marked HARRINGTON & RICHARDSON, WORCESTER, MASS. PAT. MAY 23, 1876. Approximately 3,000 were manufactured in 1877 and 1878.
Model 1¹⁄₂ .32 Caliber spur trigger, single-action revolver, 5-shot cylinder (10,000 were manufactured between 1878 and 1883)
Model 2¹⁄₂ same as model 1¹⁄₂ but 3.25-inch barrel and 7-shot cylinder (5,000 were manufactured between 1878 and 1883)
Model 3¹⁄₂ .38 rimfire Caliber 3.5-inch barrel, 5-shot cylinder (1,000 were manufactured)
Model 1880 .32 or .38 S&W centerfire double-action revolver, 3-inch round barrel, 5- or 6-shot cylinder (4,000 were manufactured between 1880 and 1883)
Young America Double Action (small solid frame centerfire revolver) Manufactured 1884–1941 Calibers: .22 rimfire and .32 Standard barrel length was 2¹⁄₂ inches, with 4¹⁄₂-inch and 5¹⁄₂-inch extra-cost options (1,500,000 were manufactured). First model manufactured 1884–1904 designed for black powder cartridge. Second model manufactured 1905–1941 designed for modern smokeless powder cartridge.
Young America Bulldog (small solid frame rimfire revolver) Caliber: .32 rimfire
Young America Safety Hammer (small solid frame centerfire revolver with bobbed hammer) Safety hammer patented 1887 Calibers: .22 and .32
Vest-Pocket Self-Cocker (same as Vest Pocket Safety Hammer but without half / full cocking sear) NOTE: Some trigger guards installed on this model had cutouts which would allow the installation of the half / full cocking sear. Early models had a 2¹⁄₂-inch octagonal barrel with front sight, later models incorporated a short 1-inch round barrel, no front sight. Calibers: .22 and .32
Vest Pocket Safety Hammer (small solid frame centerfire revolver with bobbed hammer and shortened round barrel) Safety hammer patented 1887 Calibers: .22 and .32
Victor (Unfluted cylinder, round barrel) Available in both small and large frame. Calibers: .22, .32 and .38
The American Double Action (large solid frame centerfire revolver) Manufactured 1883–1941. Calibers: .32, .38 & .44 (850,000 were manufactured).
H&R Bulldog (large solid frame rimfire revolver) Caliber: .32 rimfire
Safety Hammer Double Action (large solid frame centerfire revolver with bobbed hammer) Safety hammer patented 1887 Calibers: .32, .38 & .44 (manufactured between 1890 and 1941).
NEF Model R92 (.22 LR 9-shot revolver, .22 WMR 6-shot)
NEF Model R73 (.32 H&R Mag 5-shot)^[9]
H&R model 532
H&R model 603 (.22 WMRF six-shot pull pin revolver, Blued, Slab side barrel)
H&R model 604 (.22 WMRF six-shot pull pin revolver, Blued, Round barrel)
H&R model 622 (.22 LR six-shot pull pin revolver)
H&R model 623 (.22 LR six-shot pull pin revolver, same as 622 but in brushed nickel)
H&R model 632 (.32 cal)
H&R model 642 (.22 WMRF six shots)
H&R model 649 (.22 LR & .22 WMR six-shot, double- or single-action revolver)
H&R Model 660 Gunfighter ( .22LR Revolver, Made in the 1960s)
H&R Model 666 (.22 LR or .22 WMR, double-action with 6-inch barrel and 6-shot cylinder. Blued w/plastic grips. Manufactured from 1976 to 1982.)
H&R Model 676 (.22 LR or .22 WMR, double-action with 12-inch barrel and 6-shot cylinder. Blued w/wood grips. Manufactured from 1976 to 1980.)
H&R model 686 (.22 LR & .22 MAG)
H&R model 700
H&R model 722 (.22 LR, single-action with 6-inch octagonal barrel and 7-shot cylinder. Blued w/wood grips. Formally known as the 'Trapper' model)
H&R model 732 (.32 long six-shot swing cylinder)
H&R model 733 ( same as model 732 but in brushed nickel)
H&R model 777 Ultra Sportsman (.22 LR nine-shot revolver)
H&R model 829 (.22 LR nine-shot revolver) Swingout 9-shot cylinder, double- or single-action)

H&R model 900 9-shot .22 Revolver

H&R model 900 (.22 LR nine-shot revolver) Removable 9-shot cylinder, double- or single action, 2¹⁄₂', 4', and 6' barrels available
H&R model 904 (.22 LR nine-shot revolver) Swingout 9-shot cylinder, double-action, barrel came with a rail. Came with a wooden grip.
H&R model 922 (.22 LR nine-shot revolver)
H&R model 922-C (.22 LR nine-shot revolver) Same as 922 but with nickel finish.
H&R model 923 (.22 LR nine-shot revolver)
H&R model 925 (.32 cal. revolver)
H&R model 925 'Defender' (.38ctg five-shot revolver 4-inch barrel – blued finish)
H&R model 926 (.22 WRF nine-shot revolver)
H&R model 929 (.22 LR nine-shot revolver, blued finish)
H&R model 930 (.22 LR & nine-shot revolver, nickel finish)
H&R model 933 Hunter (.22 LR nine-shot revolver, manufactured 1930–1939.)
H&R model 925 (.38 cal. revolver)
H&R model 939 Ultra Sidekick (.22 LR double-action revolver) Introduced in 1956.^[10]
H&R model 949 (.22 LR nine-shot revolver)
H&R model 950 (.22 LR nine-shot revolver, nickel)
H&R model 999 (.22 WRF nine-shot revolver)

Note: Pre-1898 solid frame revolvers were designed for use with black powder loads. Using smokeless powder rounds with these revolvers may cause damage to the revolver and/or injury to the user.

Note: Many of the above guns are stamped as 'H&R .22 Special' / '.22 W.R.F.' or '.22 Winchester Rim Fire'

Ruger Revolver Serial Number Lookup

Pistols[edit]

H&R Self-Loading (Automatic) Pistol

H&R Self-loading (Automatic) Pistol. Calibers .32 ACP and .25 ACP.
HK4. From 1968 to 1973, Heckler & Koch's HK4 was imported from Germany and sold in the U.S. with Harrington & Richardson model HK4 branding.

Handy-Guns[edit]

H&R Handy Gun

H&R 'Handy-Gun' (single-shot top-break pistol, .410 bore, 28 gauge, 8-inch or 12¹⁄₄-inch barrel) manufactured 1920-1934^[11]
H&R 'Handy-Gun' (single-shot top-break pistol, .22 rimfire and 32-20, 12¹⁄₄-inch barrel) manufactured 1933-34^[12]

Shotguns[edit]

20 GA NEF Pardner shotgun

Pardner shotgun (Single-shot). Available in gauges 10, 12, 16, 20, 28 and in .410 bore. Youth/compact models available in short barrel 8-, 10-, and 12-inch versions prior to 1911, Turkey, Tamer, and Survivor models available in addition to the standard Pardner.
Survivor shotgun (Single-shot). Available in 410 Bore/45 Colt only. Available in either a blued finish or an electroless nickel finish with a polymer stock has a thumbhole/pistol-grip design and a convenient storage compartment.
Tamer shotgun (Single-shot). Also known as the 'Snake Tamer' is a Snake Charmer like shotgun. Available in 20 gauge or 410 Bore/45 Colt only. Available in either a blued finish or an electroless nickel finish with a polymer stock has a thumbhole/pistol-grip design. The right side of the stock is open with storage for three 20 gauge or four .410 gauge shotgun shells.
Topper shotgun (Single-shot). Available in gauges 12, 16, 20, and in .410 bore. Original models of scarce production in Youth/compact short barrel classic models, Deluxe, Classic, and Trap models available in addition to the standard Topper.
Ultra-Slug shotgun (Single-shot). Gauges 12, 20 available. Rifled barrels. Compact model available with 8,10, and 12-inch barrel for pre-1911 models. Post 1911 productions not available in compact version.
Pardner Pump shotgun (Imported). (In production). Branded NEF (New England Firearms). 12 and 20 gauges available. Manufactured by Hawk Industries, China. Youth/compact, Turkey, and Waterfowl models available in addition to the standard Pardner Pump.
Excell Auto shotgun (Discontinued). Branded NEF (New England Firearms). 12 gauge only. Manufactured in Turkey. There were waterfowl and turkey models in addition to the standard black synthetic Excell. Also came in a combo pack with both a standard and rifled barrel. Came with 4 choke tubes: IC, M, IM and F. Discontinued due to lack of parts availability.
Pinnacle (Double barrel). (Discontinued).
Gamester (Bolt action). Gauges 16 and 12. Example: Model 349

Rifles[edit]

Handi-Rifle (Single-shot): Calibers: .17 HMR, .204 Ruger, .22 LR, .22 WMR, .22-250 Remington, .223 Remington, .243 Winchester, .25-06 Remington, .270 Winchester, .280 Remington, 7mm-08 Remington, .308 Winchester, .30-06 Springfield.30-30 Winchester, 300AAC Blackout, .444 Marlin, .45 LC, .45/70 Government, and .500 S&W. Also available with pairs of handgun/rifled slug barrels in .357 Magnum/20-gauge and .44 Magnum/12-gauge.^[13] Standard, Synthetic, Superlight, Ultra Varmint, Ultra Hunter, Buffalo Classic, CR Carbine, and Sportster models available. A version with a 16' threaded barrel chambered in .300 AAC Blackout is made for Advanced Armament Corporation.^[14]
H&R 330: Made from 1968 to 1972, this model is an FN Mauser action that Harrington and Richardson bought as surplus and produced into sporterized hunting rifles using Douglas barrels and conventional stocks, chambered in 7mm Remington Magnum.^[15]
H&R M12 5200: A competitor to the Winchester Model 52 series rifle. Bolt action .22 LR single-shot rifle. Featured a heavy 28-inch barrel of blued steel, an oversized, walnut stock with an accessory rail in the fore end.
H&R Model 700: .22 Magnum semi auto rifle
H&R Model 765/766 'Pioneer': Produced as the 766 from 1949 to 1950 in a nickel finish while the 765 was made between 1950 to 1951 with a blued finish. .22 S/L/LR, single shot bolt action.
H&R Model 760 ': .22LR Produced in 1967,1968 and 1971. single shot automatic.

Military[edit]

Reising Submachine Gun

Reising Submachine Gun: Produced during WWII.
M1: Harrington & Richardson was assigned serial number ranges 4660001 through 4800000, 5488247 through 5793847, and 400 rifles numbered from 6034330 through 6034729. The major components, such as the barrel, bolt, hammer, operating rod, safety, and trigger housing were stamped with a numeric drawing number and the manufacturer's initials. Harrington & Richardson rifles are marked HRA on all marked parts except the receivers, which were stamped H&R ARMS CO.^[16]
M14: H&R had the largest contract (1959–1964) of four manufacturers (H&R, Winchester, The Springfield Armory, and Thompson-Ramo-Wooldridge (TRW)), to produce the M14 rifle.
M16A1: Working under another U.S. military contract during the Vietnam War, H&R is one of only four companies (Colt, Fabrique National, General Motors Hydramatic Division, and H&R), to have made M16 variants for the U.S. military.
T223 Rifle: Licensed copy of the Heckler & Koch HK33 Assault Rifle.

Notes[edit]

^ ^a^b'About Us' by Harrington & Richardson at the H&R 1871 website
^Molina, Roger (2011). My Life, Our Lives. iUniverse. p. 652. ISBN978-1-4502-9649-6.
^Walgreens Store locator
^Flayderman, Norm (3 December 2007). Flayderman's Guide to Antique American Firearms and Their Values. Gun Digest Books. p. 274. ISBN1-4402-2651-2.
^Schroeder, Joseph (24 August 2007). Gun Digest Handbook Collectible American Guns. Iola, Wisconsin: Gun Digest Books. p. 77. ISBN1-4402-2663-6.
^https://www.google.com/patents/US1984677
^https://www.google.com/patents/US1572262
^https://www.google.com/patents/US2388766
^Warner, Ken (1990). Gun Digest 1991 45th Annual Edition. DBI Books. p. 292.
^Smith, Walter Harold Black; Joseph Edward Smith (1968). The W.H.B. Smith Classic Book of Pistols. Stackpole Books. p. 739.
^The .410 bore and 28 gauge H&R 'Handy-Gun' are smooth bore pistols, regulated under the National Firearms Act of 1934 (NFA), and must be registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) as an 'Any Other Weapon'. 'Any Other Weapon', as defined in 26 U.S.C., § 5845(e), means any weapon or device capable of being concealed on the person from which a shot can be discharged through the energy of an explosive, a pistol or revolver having a barrel with a smooth bore designed or redesigned to fire a fixed shotgun shell, weapons with combination shotgun and rifle barrels 12 inches or more, less than 18 inches in length, from which only a single discharge can be made from either barrel without manual reloading, and shall include any such weapon which may be readily restored to fire. Such term shall not include a pistol or revolver having a rifled bore, or rifled bores, or weapons designed, made, or intended to be fired from the shoulder and not capable of firing fixed ammunition.
^A rifled-barrel H&R 'Handy-Gun' is not subject to the National Firearms Act of 1934 unless accompanied by a shoulder stock.
^http://www.hr1871.com/Firearms/Combos/handislug.asp
^'Advanced Armament Corp. Announces Handi-Rifle Chambered in 300 AAC Blackout'. Ammoland. September 17, 2012.
^2010 Standard Catalog of Firearms, 2009, Krause Publications, Inc.
^Excerpted from The M1 Garand: Owner's Guide, 1994, Scott A. Duff.

References[edit]

Crane, Ellery Bicknell (1907). Historic Homes and Institutions and Genealogical and Personal Memoirs of Worcester County, Massachusetts: With a History of Worcester Society of Antiquity. Lewis Pub. p. 1834.
Larson, Eric Martin (1993). Variations of the Smooth Bore H&R Handy-Gun: A Pocket Guide to Their Identification. Takoma Park, Maryland: The Author. pp. 65. ISBN No. 0-9636465-0-8.
Rice, Franklin Pierce (1899). Worcester of Eighteen Hundred and Ninety-eight: Fifty Years a City : a Graphic Representation of Its Institutions, Industries, and Leaders. F.S. Blanchard. p. 809.

External links[edit]

Retrieved from 'https://en.wikipedia.org/w/index.php?title=H%26R_Firearms&oldid=898368302'

The h-index is an author-level metric that attempts to measure both the productivity and citation impact of the publications of a scientist or scholar. The index is based on the set of the scientist's most cited papers and the number of citations that they have received in other publications. The index can also be applied to the productivity and impact of a scholarly journal^[1] as well as a group of scientists, such as a department or university or country.^[2] The index was suggested in 2005 by Jorge E. Hirsch, a physicist at UC San Diego, as a tool for determining theoretical physicists' relative quality^[3] and is sometimes called the Hirsch index or Hirsch number.

Definition and purpose[edit]

h-index from a plot of decreasing citations for numbered papers

The h-index is defined as the maximum value of h such that the given author/journal has published h papers that have each been cited at least h times.^[4] The index is designed to improve upon simpler measures such as the total number of citations or publications. The index works properly only for comparing scientists working in the same field; citation conventions differ widely among different fields.

Calculation[edit]

Formally, if f is the function that corresponds to the number ofcitations for each publication, we compute the h index as follows.First we order the values of f from the largest to the lowest value.Then, we look for the last position in which f is greater than or equal to theposition (we call h this position).For example, if we have a researcher with 5 publications A, B, C, D, and Ewith 10, 8, 5, 4, and 3 citations, respectively, the h index is equalto 4 because the 4th publication has 4 citations and the 5th has only 3.In contrast, if the same publications have 25, 8, 5, 3, and 3 citations, then theindex is 3 because the fourth paper has only 3 citations.

f(A)=10, f(B)=8, f(C)=5, f(D)=4, f(E)=3　→ h-index=4

f(A)=25, f(B)=8, f(C)=5, f(D)=3, f(E)=3　→ h-index=3

If we have the function f ordered in decreasing order from the largestvalue to the lowest one, we can compute the h index as follows:

h-index (f) =

{displaystyle max _{i}min(f(i),i)}

The Hirsch index is analogous to theEddington number, an earlier metric used for evaluating cyclists.The h-index serves as an alternative to more traditional journal impact factor metrics in the evaluation of the impact of the work of a particular researcher. Because only the most highly cited articles contribute to the h-index, its determination is a simpler process. Hirsch has demonstrated that h has high predictive value for whether a scientist has won honors like National Academy membership or the Nobel Prize. The h-index grows as citations accumulate and thus it depends on the 'academic age' of a researcher.

Input data[edit]

The h-index can be manually determined using citation databases or using automatic tools. Subscription-based databases such as Scopus and the Web of Science provide automated calculators. Harzing's Publish or Perish program calculates the h-index based on Google Scholar entries. From July 2011 Google have provided an automatically-calculated h-index and i10-index within their own Google Scholar profile.^[5] In addition, specific databases, such as the INSPIRE-HEP database can automatically calculate the h-index for researchers working in high energy physics.

Each database is likely to produce a different h for the same scholar, because of different coverage.^[6] A detailed study showed that the Web of Science has strong coverage of journal publications, but poor coverage of high impact conferences. Scopus has better coverage of conferences, but poor coverage of publications prior to 1996; Google Scholar has the best coverage of conferences and most journals (though not all), but like Scopus has limited coverage of pre-1990 publications.^[7]^[8] The exclusion of conference proceedings papers is a particular problem for scholars in computer science, where conference proceedings are considered an important part of the literature.^[9] Google Scholar has been criticized for producing 'phantom citations,' including gray literature in its citation counts, and failing to follow the rules of Boolean logic when combining search terms.^[10] For example, the Meho and Yang study found that Google Scholar identified 53% more citations than Web of Science and Scopus combined, but noted that because most of the additional citations reported by Google Scholar were from low-impact journals or conference proceedings, they did not significantly alter the relative ranking of the individuals. It has been suggested that in order to deal with the sometimes wide variation in h for a single academic measured across the possible citation databases, one should assume false negatives in the databases are more problematic than false positives and take the maximum h measured for an academic.^[11]

Comparing results across fields and career levels[edit]

Little systematic investigation has been done on how the h-index behaves over different institutions, nations, times and academic fields.^{[citation needed]} Hirsch suggested that, for physicists, a value for h of about 12 might be typical for advancement to tenure (associate professor) at major [US] research universities. A value of about 18 could mean a full professorship, 15–20 could mean a fellowship in the American Physical Society, and 45 or higher could mean membership in the United States National Academy of Sciences.^[12] Hirsch estimated that after 20 years a 'successful scientist' would have an h-index of 20, an 'outstanding scientist' would have an h-index of 40, and a 'truly unique' individual would have an h-index of 60.^[3]

For the most highly cited scientists in the period 1983–2002, Hirsch identified the top 10 in the life sciences (in order of decreasing h): Solomon H. Snyder, h = 191; David Baltimore, h = 160; Robert C. Gallo, h = 154; Pierre Chambon, h = 153; Bert Vogelstein, h = 151; Salvador Moncada, h = 143; Charles A. Dinarello, h = 138; Tadamitsu Kishimoto, h = 134; Ronald M. Evans, h = 127; and Axel Ullrich, h = 120. Among 36 new inductees in the National Academy of Sciences in biological and biomedical sciences in 2005, the median h-index was 57.^[3] However, Hirsch noted that values of h will vary between different fields.^[3]

Among the 22 scientific disciplines listed in the Thomson Reuters Essential Science Indicators Citation Thresholds [thus excluding non-science academics], physics has the second most citations after space science.^[13] During the period January 1, 2000 – February 28, 2010, a physicist had to receive 2073 citations to be among the most cited 1% of physicists in the world.^[13] The threshold for space science is the highest (2236 citations), and physics is followed by clinical medicine (1390) and molecular biology & genetics (1229). Most disciplines, such as environment/ecology (390), have fewer scientists, fewer papers, and fewer citations.^[13] Therefore, these disciplines have lower citation thresholds in the Essential Science Indicators, with the lowest citation thresholds observed in social sciences (154), computer science (149), and multidisciplinary sciences (147).^[13]

Numbers are very different in social science disciplines: The Impact of the Social Sciences team at London School of Economics found that social scientists in the United Kingdom had lower average h-indices. The h-indices for ('full') professors, based on Google Scholar data ranged from 2.8 (in law), through 3.4 (in political science), 3.7 (in sociology), 6.5 (in geography) and 7.6 (in economics). On average across the disciplines, a professor in the social sciences had an h-index about twice that of a lecturer or a senior lecturer, though the difference was the smallest in geography.^[14]

Advantages[edit]

Hirsch intended the h-index to address the main disadvantages of other bibliometric indicators, such as total number of papers or total number of citations. Total number of papers does not account for the quality of scientific publications, while total number of citations can be disproportionately affected by participation in a single publication of major influence (for instance, methodological papers proposing successful new techniques, methods or approximations, which can generate a large number of citations), or having many publications with few citations each. The h-index is intended to measure simultaneously the quality and quantity of scientific output.

Criticism[edit]

There are a number of situations in which h may provide misleading information about a scientist's output:^[15] Most of these however are not exclusive to the h-index.

H&r Revolver Serial Number Lookup

The h-index does not account for the typical number of citations in different fields. It has been stated that citation behavior in general is affected by field-dependent factors,^[16] which may invalidate comparisons not only across disciplines but even within different fields of research of one discipline.^[17]
The h-index discards the information contained in author placement in the authors' list, which in some scientific fields is significant.^[18]^[19]
The h-index has been found in one study to have slightly less predictive accuracy and precision than the simpler measure of mean citations per paper.^[20] However, this finding was contradicted by another study by Hirsch.^[21]
The h-index is a natural number that reduces its discriminatory power. Ruane and Tol therefore propose a rationalh-index that interpolates between h and h + 1.^[22]
The h-index can be manipulated through self-citations,^[23]^[24]^[25] and if based on Google Scholar output, then even computer-generated documents can be used for that purpose, e.g. using SCIgen.^[26]
The h-index does not provide a significantly more accurate measure of impact than the total number of citations for a given scholar. In particular, by modeling the distribution of citations among papers as a random integer partition and the h-index as the Durfee square of the partition, Yong^[27] arrived at the formula ${displaystyle happrox 0.54{sqrt {N}}}$ , where N is the total number of citations, which, for mathematics members of the National Academy of Sciences, turns out to provide an accurate (with errors typically within 10–20 percent) approximation of h-index in most cases.

Alternatives and modifications[edit]

Various proposals to modify the h-index in order to emphasize different features have been made.^[28]^[29]^[30]^[31]^[32]^[33] As the variants have proliferated, comparative studies have become possible showing that most proposals are highly correlated with the original h-index and therefore largely redundant,^[34] although alternative indexes may be important to decide between comparable CVs, as often the case in evaluation processes.

An individual h-index normalized by the number of authors has been proposed: ${displaystyle h_{I}=h^{2}/N_{a}^{(T)}}$ , with ${displaystyle N_{a}^{(T)}}$ being the number of authors considered in the ${displaystyle h}$ papers.^[28] It was found that the distribution of the h-index, although it depends on the field, can be normalized by a simple rescaling factor. For example, assuming as standard the hs for biology, the distribution of h for mathematics collapse with it if this h is multiplied by three, that is, a mathematician with h = 3 is equivalent to a biologist with h = 9. This method has not been readily adopted, perhaps because of its complexity. It might be simpler to divide citation counts by the number of authors before ordering the papers and obtaining the h-index, as originally suggested by Hirsch.
The m-index is defined as h/n, where n is the number of years since the first published paper of the scientist;^[3] also called m-quotient.^[35]^[36]
There are a number of models proposed to incorporate the relative contribution of each author to a paper, for instance by accounting for the rank in the sequence of authors.^[37]
A generalization of the h-index and some other indices that gives additional information about the shape of the author's citation function (heavy-tailed, flat/peaked, etc.) has been proposed.^[38]
Three additional metrics have been proposed: h² lower, h² center, and h² upper, to give a more accurate representation of the distribution shape. The three h² metrics measure the relative area within a scientist's citation distribution in the low impact area, h² lower, the area captured by the h-index, h² center, and the area from publications with the highest visibility, h² upper. Scientists with high h² upper percentages are perfectionists, whereas scientists with high h² lower percentages are mass producers. As these metrics are percentages, they are intended to give a qualitative description to supplement the quantitative h-index.^[39]
The g-index can be seen as the h-index for an averaged citations count.^[40]
It has been argued that 'For an individual researcher, a measure such as Erdős number captures the structural properties of network whereas the h-index captures the citation impact of the publications. One can be easily convinced that ranking in coauthorship networks should take into account both measures to generate a realistic and acceptable ranking.' Several author ranking systems such as eigenfactor (based on eigenvector centrality) have been proposed already, for instance the Phys Author Rank Algorithm.^[41]
The c-index accounts not only for the citations but for the quality of the citations in terms of the collaboration distance between citing and cited authors. A scientist has c-index n if n of [his/her] N citations are from authors which are at collaboration distance at least n, and the other (N − n) citations are from authors which are at collaboration distance at most n.^[42]
An s-index, accounting for the non-entropic distribution of citations, has been proposed and it has been shown to be in a very good correlation with h.^[43]
The e-index, the square root of surplus citations for the h-set beyond h², complements the h-index for ignored citations, and therefore is especially useful for highly cited scientists and for comparing those with the same h-index (iso-h-index group).^[44]^[45]
Because the h-index was never meant to measure future publication success, recently, a group of researchers has investigated the features that are most predictive of future h-index. It is possible to try the predictions using an online tool.^[46] However, later work has shown that since h-index is a cumulative measure, it contains intrinsic auto-correlation that led to significant overestimation of its predictability. Thus, the true predictability of future h-index is much lower compared to what has been claimed before.^[47]
The i10-index indicates the number of academic publications an author has written that have been cited by at least ten sources. It was introduced in July 2011 by Google as part of their work on Google Scholar.^[48]
The h-index has been shown to have a strong discipline bias. However, a simple normalization ${displaystyle h/langle hrangle _{d}}$ by the average h of scholars in a discipline d is an effective way to mitigate this bias, obtaining a universal impact metric that allows comparison of scholars across different disciplines.^[49] Of course this method does not deal with academic age bias.
The h-index can be timed to analyze its evolution during one's career, employing different time windows.^[50]
The o-index corresponds to the geometric mean of the h-index and the most cited paper of a researcher.^[51]
The RA-index accommodates improving the sensitivity of the H-index on the number of highly cited papers and has many cited paper and uncited paper under the H-core. This improvement can enhance the measurement sensitivity of the H-index. ^[52]