The Camino Verde trial of community mobilisation for control of dengue reported a significant impact on entomological indices of the Aedes aegypti vector , and on serological dengue virus infection and self-reported dengue cases .
One reason for doing r and omised controlled trials ( RCTs ) is that experiments can be convincing .
Early epidemiological experimenters , such as Jenner and the smallpox vaccine and Snow and his famous Broad Street pump h and le , already knew the answer they were demonstrating ; they used the experiments as knowledge translation devices to convince others .
More sophisticated modern experiments include cluster r and omised controlled trials ( C RCTs ) for experiments in the public health setting .
Those who are convinced by a trial and want to act , need to know how the trial relates to their own context , what contributed to success , and what might make it even more effective .
The women made it work: fuzzy transitive closure of the results chain in a dengue prevention trial in Mexico
Background A modified theory of planned behaviour ( acronym CASCADA ) proposes that Conscious knowledge precedes a change in Attitude , which in turn precedes positive deviations from negative Subjective norms , intention to Change , perception of Agency to change , Discussion of possible action , and Action itself . We used this as a results chain to investigate gender-specific behaviour dynamics in chemical-free dengue prevention . Methods Secondary analysis of the Mexican arm of a cluster r and omised controlled trial used household survey data on intermediate outcomes of dengue prevention behaviour . We used a matrix of odds ratios between outcomes , transformed to a symmetrical range ( −1 , 1 ) , to compute fuzzy transitive closure of the results chain for  control and intervention clusters , then for male and female respondents separately in each group . Transitive closure of a map computes the influence of each factor on each other factor , taking account of all influences in the system . Cumulative net influence was the sum of influences across the results chain . Results Responses of 5042 women and 1143 men in 45 intervention clusters contrasted with those of 5025 women and 1179 men in 45 control clusters . Control clusters showed a distal block ( negative influence ) in the results chain with a cumulative net influence of 0.88 ; intervention clusters showed no such block and a cumulative net influence of 1.92 . Female control respondents , like the overall control picture , showed a distal block , whereas female intervention responses showed no such blocks ( cumulative net influence 0.78 and 1.73 respectively ) . Male control respondents showed weak distal blocks . Male intervention responses showed several new negative influences and a reduction of cumulative net influence ( 1.38 in control and 1.11 in intervention clusters ) . Conclusions The overall influence of the intervention across the results chain fits with the trial findings , but is different for women and men . Among women , the intervention overcame blocks and increased the cumulative net influence of knowledge on action . Among men , the intervention did not reinforce prevention behaviour . This might be related to emphasis , during the intervention , on women ’s participation and empowerment . The fuzzy transitive closure of the CASCADA map usefully highlights the differences between gender-specific results chains . Trial registration IS RCT N27581154
The Camino Verde trial of community mobilisation for control of dengue reported a significant impact on entomological indices of the Aedes aegypti vector , and on serological dengue virus infection and self-reported dengue cases .
One reason for doing r and omised controlled trials ( RCTs ) is that experiments can be convincing .
Early epidemiological experimenters , such as Jenner and the smallpox vaccine and Snow and his famous Broad Street pump h and le , already knew the answer they were demonstrating ; they used the experiments as knowledge translation devices to convince others .
More sophisticated modern experiments include cluster r and omised controlled trials ( C RCTs ) for experiments in the public health setting .
Those who are convinced by a trial and want to act , need to know how the trial relates to their own context , what contributed to success , and what might make it even more effective .