Randomisation ceremonies: from ping-pong to football matches

Richard Hayes

JAMA 1995; 273: 408-412 2,838 citations

Aims of public randomisation ceremonies

• To explain background to trial• To explain need for random allocation and

procedures to be used for this• To carry out randomisation using transparent

procedure, involving key stakeholders Rationale is to ensure fairness, transparency, buy-in,

engagement

Stakeholders: Government representatives, community leaders, community representatives

Ghana bednet trial

• Rural area of Northern Ghana• Widely scattered households• Divided into 96 clusters of geographically contiguous

households - average of 1400 persons per cluster• 48 clusters: impregnated bednets• 48 clusters: control arm – bednets at end of trial• Mortality in children (6-59m) reduced by 17%• Randomisation carried out by lottery in 10 paramount

chiefdoms in study area

Binka et al, TMIH 1996, 1: 147-154

Ghana bednet trial

MEMA kwa Vijana trial• 20 rural communities in Mwanza Region, Tanzania• Adolescent sexual health intervention

– In-school sexual health education– Youth-friendly services– Youth condom distributors

• Cohort of 9,645 young people (Av age 15.5y) followed up for 36 months

• Further cross-sectional survey carried out 5-6y later• Effects on knowledge, attitudes and some reported

sexual behaviours• No impact on HIV, pregnancy, other STIs

Ross et al, AIDS 2007, 21:1943 Doyle et al, PLoSMed 2010, 7:e1000287

MEMA kwa Vijana trial

MkV randomisation scheme

• 20 clusters divided into three strata based on initial survey of HIV prevalence– High-risk: 6 clusters– Medium-risk: 8 clusters– Low-risk: 6 clusters

• Stratified randomisationPossible allocations = 6C4

x 8C3 x 6C3 = 28,000

MkV restricted randomisation• Restricted randomisation

– Used to ensure adequate balance across study arms

• Restriction criteria– Mean HIV prevalence similar– Mean chlamydia prevalence similar– Two communities near mines evenly distributed– Even distribution over four districts

• 953 of the 28,000 allocations satisfied criteria

Hayes et al, Contemporary Clinical Trials 2005, 26:430

MkV randomisation ceremony

• Held with senior stakeholders• List of allocations presented, numbered 001–953• Stakeholders asked to draw ping-pong balls

numbered 0-9 from bucket• Number 039 selected: divides 20 communities

into two sets of 10• Final draw of ping-pong ball used to decide which

set of 10 receives intervention

Zamstar trial• Impact of 2 intensive TB control strategies

evaluated in 2x2 factorial CRT– Arm 1: Enhanced case finding– Arm 2: Household intervention– Arm 3: ECF + household– Arm 4: Neither intervention

• 24 communities in Zambia and S Africa• Household intervention decreased TB prevalence

by 20% and reduced transmission to children• No effect of ECF

Ayles et al, Trials 2008, 9:63

Zamstar randomisation scheme

• 24 clusters divided into 4 strata based on initial TST survey in schoolchildren– Zambia/High TST: 8 clusters– Zambia/Low TST: 8 clusters– S Africa/High TST: 4 clusters– S Africa/Low TST: 4 clusters

• Stratified randomisationPossible allocations =

= 3,657,830,400

Zamstar restricted randomisation• Restriction criteria

– Similar number with high estimated HIV prevalence in each arm

– Similar mean TST prevalence– Similar number of “open” communities– Similar number of urban communities– Political constraints

• Randomly selected allocations until 1,000 which satisfied restriction criteria

Sismanidis et al, Clin Trials 2008, 5:316

Zamstar randomisation ceremony

• Held on football pitch during tournament in Zambia

• List of acceptable allocations numbered 000-999• 24 volunteers representing clusters• Senior officials asked to draw footballs numbered

0-9 from sack• Number 773 selected: volunteers divided into four

groups labelled A-D• More footballs drawn to determine study arm

allocated to each group

Special thanks to

• Fred Binka for the Ghana video• Babis Sismanidis for the Zamstar video• The PIs and investigators of the Ghana bednet,

MkV and Zamstar trials