Watkins 1996a.

Methods	Design: parallel group randomized trial Duration of study: February to October 1993 Follow‐up: 14 days
Participants	Country: Republic of Guatemala Setting: school Number included in study: 246 Age: ≤ 12 years(mean 9.8 years) Sex: not reported Inclusion criteria: girls and boys aged ≤ 12 years who had not taken any deworming medicine in the past year Exclusion criteria: pregnancy Lost at follow‐up: 22 (8.8%) Number positive for A lumbricoides: 209 Number included in review: 209
Interventions	Treatment strategy: screening and treat all included participants Group 1: albendazole 200 mg 2 tablets single dose (n = 106) Group 2: placebo (n = 103)
Outcomes	Outcomes included:Ascaris cure rates and pre‐ and post‐treatment AM and GM epg Outcomes not included in review: anthropometric measures, anthelmintic efficacy for Trichuris
Notes	Diagnostic technique: modified Kato‐Katz Funding support: Pew Charitable Trusts, the US Agency for International Development University Development and Linkage Program, the Children's Miracle Network Telethon, and the ARCS Foundation
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Children were stratified by sex and age and then randomly assigned."
Allocation concealment (selection bias)	Unclear risk	Details not reported.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "The children and field workers were unaware of treatment group assignment."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Although the 2‐week posttreatment egg examination made it clear to the study director, which treatment was which, this information was not communicated to the field workers."
Incomplete outcome data (attrition bias) All outcomes	Low risk	22 (8.8%) participants lost at follow‐up and not included in analysis.
Selective reporting (reporting bias)	High risk	Adverse events not reported.
Other bias	Low risk	No obvious source of other bias.