Table 1 Characteristics of the included studies by type of study and publication year

Tsung-Hsueh, Lu et al. [37]

2006

1.1-31.12.2002

Taiwan (nationwide)

All

S, U

Re-evaluated DC

3993

Fair quality of mode of death certification (MOD).

Carr J.R. et al. [36]

2004

1998-1999

USA (nationwide)

US Military

A*, U, H and deaths occurred within 30 days of retirement

Re-evaluated DC, AR, TR, CR, MJ and investigative agency reports

1844

Concluded 21% underestimation.

Found 17% underreporting, and additional 4% of deaths that were suspicious for suicide.

Ahlm, K. et al. [33]

2001

1999

Sweden (nationwide)

All

Traffic deaths

Re-evaluated AR, DC, MJ and PR

580

¶ 1.5% under-reporting.

Found 3% (18 of 580) suicides among the officially registered accidental traffic deaths.

Sampson, H.M. and Rutty, G.N [31]

1999

1992-1997

South Yorkshire (West), England

All

S, OV

Re-evaluated MJ, AR, and SN

295

Official national data may under-report the annual suicide rate by over 20%.

Ohberg, A. et al. [30]

1998

1.4.1987 - 31.3.1988

Finland (nationwide)

All

U

Re-evaluated MJ and psychological autopsies.

139

Undetermined deaths resembled suicides and appeared to reduce the suicide rate by 10%

Connolly, J.F. and Cullen, A [28]

1995

1978-1992

County Mayo, Ireland

All

S, A**, U

Re-evaluated DC, MJ

220

35% deaths were miscoded (n = 56) or unregistered (n = 16).

O'Donnell, I. and Farmer, R [29]

1995

A 5-year study period

London (England)

All

S (deaths on the London Underground railway system)

Re-evaluated. Records from LUL and the British Transport Police. Prospective design

242

Substantial underestimation of the true number of suicides.

Verdicts other than suicide were returned on 25% and 50% of the women and men, respectively.

Scott, K.W.M [26]

1994

1976-1990

The borough of Wolverhampton (250.566) (England)

All

S

Re-evaluated AR

394

¶¶ 69% under-reporting.

Estimated suicide rate of 10.5/100,000 per year. The official suicide rate were 6.2/100 000 per year. The coroners only reflected 59% of the probable true suicide rate.

Allebeck, P. et al. [24]

1991

1969-1983

Sweden (nationwide)

Males conscripted for military service in 1969-70

CO, S, U, TD

Re-evaluated DC, PR, MJ, TR and AR in a cohort of 50.465

322

High accuracy. Findings indicate an underreporting of suicide in cases of poisoning and other undetermined cases.

Rodriguez-Pulido, F. et al. [23]

1991

1977-1983

Canary Islands (Spain)

All

VD, ND

Re-evaluated AR, SN, TE and JP

775

¶¶ 104% under-reporting.

Lack of validity and reliability of official figures of suicide. Recorded 8.1/100,000 suicides per year. The official published statistics recorded 3.98/100,000 per year for the same period. This represents 49% of which was found in this study.

Walsh, D.et al. [22]

1990

1978-1987

County Kildare, County Dublin and Dublin city (Ireland)

All

S, A, U

Re-evaluated CR

-

¶¶ 5% under-reporting.

Reflecting the suicide rate accurately.

Estimated 5.9/100,000 suicides per year. The official suicide rate were 5.6/100,000.

Huusko, R. and Hirvonen, J [20]

1988

1981

Oulu, Finland

All

S, A, U

Re-evaluated PR, AR and MJ

283

The official figure for suicides could be as much as 18.9% too low.

Ekeberg, Ø. et al. [17]

1985

24.5.1978 - 26.4.1981

Norway (except Hordaland and Sogn og fjordane)

All

DI, D

Re-evaluated AR

210

Underregistration of 10%

Malla, A. and Hoenig, J [16]

1983

1974-1978

Newfoundland (Canada)

All

S, CO

Re-evaluated DC and AR

104

¶¶ 12% under-reporting.

Study suicide rate of 4.25/100,000 suicides per year, compared to the official rate of 3.8/100,000 per year.

Clarke-Finnegan, M. and Fahy, T. J [15]

1983

1978

Galway, Ireland

All

All deaths except natural deaths and TD

Re-evaluated AR

410

¶¶ 126% under-reporting.

A minimum true rate of suicide was 13.1/100,000. The officially reported suicide rate was 5.8/100,000.

De Faire, U. et al. [13]

1976

1961-1973

Sweden (nationwide)

Twins born in 1901-1925

All deaths

Cohort of twins. Re-evaluated MJ, AR and PR

1156

Mortality data on suicide are fairly valid for use in epidemiological studies and mortality statistics with regard to suicides.

McCarthy, P. D. and Walsh, D [11]

1975

1964-1968

Dublin (Ireland)

All

All deaths investigated by Dublin city and county coroners

Re-evaluated CR, MJ

210

¶¶ 279% under-reporting.

Official suicide rate of 1.4 per 100,000 and study-rate of 5.3 per 100,000.

Ovenstone, I.M.K [9]

1973

Oct.1969 - March 1971

Edinburgh (Scotland)

All

S, A, U and gas poisonings

Re-evaluated MJ

214

Suicide rate was underestimated by approximately 50% by the Crown Counsel.

The Crown counsel under-reporting suicide by 40.6% and the Scottish Registrar General 32%.

Litman, R.E. et al. [8]

1963

1959-1960

Los Angeles County

All

Equivocal suicides

Re-evaluated PR, AR and interviewed survivors of the deceased.

100

Significant underreporting.

Combined re-evaluation and registry studies

Cantor, C. et al. [32]

2001

1990-1995

Queensland, Australia

All

Suicide beyond no reasonable doubt, probable and possible suicide

Registry study and re-evaluated PR and AR

2728

5.5% more suicides registered in QSR than the official ABS count for the period.

141 of the deaths coded as probable/possible suicides (675) by the QSR were rejected as being deaths other than suicide - usually accidental overdoses.

Thorslund, J et al. [21]

1989

1977-1986

Greenland

All

S, CO

Registry study and Re-evaluated DC and PR

442

The official statistics are generally reliable.

Registry studies

Elnour, A.A. and Harrison, J [38]

2009

July 2000 - the end of 2005

Australia (nationwide)

All

S

Registry study

12786

About 8% underestimation

Lahti, R.A. and Vuori, E [35]

2003

1997

Finland (nationwide)

All

DPD; A, S, U

Registry study

500

Fairly good agreement. 98.5% agreement

Lindeman S.M. et al. [27]

1995

1986-1991

Finland (nationwide)

All

S, U, A***

Registry study

17 412

Reliable enough. 97% coverage.

Van de Voorde, H. et al. [25]

1993

1981-1984

Leuven (Belgium)

All

S

Registry study

323

Incidence reporting bias of 4-8%.

311 suicides found in one registry (PPO) and 323 suicides in the other registry (NIS).

Gary Hlady, W. and Middaugh, J.P [19]

1988

1983-1984

Alaska

All

S

Registry study

195

Severely under-recorded suicides.

Marshall, D.L. and Soule, S [18]

1988

1979-1984

49 predominantly Native villages in southwest Alaska

All

VD; S, A, U, H

Registry study

220

¶¶405% under-reporting.

Native suicide rate 36.9/100,000 (n = 38), compared to official suicide rate 7.3/100,000 (n = 5).

"Other re-evaluation studies"

Joseph, A. et al. [34]

2003

1994-1999

Kaniyambadi region, southern India

All

-

Verbal autopsies

-

Mean suicide rate was 95.2/100,000 (range 83.7-106.3/100,000) - nine times the national average

Warshauer, M.E. and Monk, M [14]

1978

1968-1970

An area of New York City; East Harlem in Manhattan and three districts in the South Bronx. (USA)

All

S, "assigned" suicide

Comparing published Health Department suicide rates with medical examiner records

-

Suicides among the black population were underestimated by 80% and those among whites by 42%. Suicide rates were greatly affected by the change in revision of the ICD.

Atkinson, M.W. et al. [10]

1975

-

England and Denmark (nationwide)

All

Probable suicide

Compared suicide ascertainment procedure between Denmark and England.

40

Danes consistently report more suicides than do the English coroners

Ross, O. and Kreitman, N [12]

1975

-

England, Wales, Scotland (nationwide)

All

S, U, OV

A two-way exchange of case records

264

The results strongly suggest that the two sets of officials share roughly the same criteria.