Yuriko: Our city' s campaign to persuade parents to have their children vaccinated ought to be imitated by your city  In the 16 months since the enactment of legislation authorizing the campaign, vaccinations in our city have increased by 30 percent
Susan: But the major part of that increase occurred in the first 6 months after that legislation was enacted, right after your city' s free neighborhood health clinics opened, and before the vaccination campaign really got going
She cites facts that tend to weaken the force of the evidence with which Yuriko supports her recommendation.