NEWCASTLE - OTTAWA QUALITY ASSESSMENT SCALE
CASE CONTROL STUDIES
Note: A study can be awarded a maximum of one star for each numbered item within the Selection andExposure categories. A maximum of two stars can be given for Comparability.

Selection
1) Is the case definition adequate?
a) yes, with independent validation ¯b) yes, eg record linkage or based on self reportsc) no description
2) Representativeness of the casesa) consecutive or obviously representative series of cases ¯b) potential for selection biases or not stated
3) Selection of Controlsa) community controls ¯b) hospital controlsc) no description4) Definition of Controlsa) no history of disease (endpoint) ¯b) no description of source

Comparability1) Comparability of cases and controls on the basis of the design or analysisa) study controls for _______________ (Select the most important factor.) ¯b) study controls for any additional factor ¯ (This criteria could be modified to indicate specificcontrol for a second important factor.)

Exposure
1) Ascertainment of exposurea) secure record (eg surgical records) ¯b) structured interview where blind to case/control status ¯c) interview not blinded to case/control statusd) written self report or medical record onlye) no description2) Same method of ascertainment for cases and controlsa) yes ¯b) no3) Non-Response ratea) same rate for both groups ¯b) non respondents describedc) rate different and no designation

NEWCASTLE - OTTAWA QUALITY ASSESSMENT SCALECOHORT STUDIES
Note: A study can be awarded a maximum of one star for each numbered item within the Selection andOutcome categories. A maximum of two stars can be given for Comparability

Selection1) Representativeness of the exposed cohorta) truly representative of the average _______________ (describe) in the community ¯b) somewhat representative of the average ______________ in the community ¯c) selected group of users eg nurses, volunteersd) no description of the derivation of the cohort
2) Selection of the non exposed cohorta) drawn from the same community as the exposed cohort ¯b) drawn from a different sourcec) no description of the derivation of the non exposed cohort3) Ascertainment of exposurea) secure record (eg surgical records) ¯b) structured interview ¯c) written self reportd) no description4) Demonstration that outcome of interest was not present at start of studya) yes ¯b) noComparability
1) Comparability of cohorts on the basis of the design or analysisa) study controls for _____________ (select the most important factor) ¯b) study controls for any additional factor ¯ (This criteria could be modified to indicate specificcontrol for a second important factor.)

Outcome1) Assessment of outcomea) independent blind assessment ¯b) record linkage ¯c) self reportd) no description2) Was follow-up long enough for outcomes to occura) yes (select an adequate follow up period for outcome of interest) ¯b) no3) Adequacy of follow up of cohortsa) complete follow up - all subjects accounted for ¯b) subjects lost to follow up unlikely to introduce bias - small number lost - > ____ % (select anadequate %) follow up, or description provided of those lost) ¯c) follow up rate < ____% (select an adequate %) and no description of those lostd) no statement