The serial interval (SI) is NOT one of the estimators.   

<p>The SI is a parameter required by all of the estimators, and can also be estimated by the WP method.</p>

<p>The SI is defined as the average time between successive infections in a chain of transmission i.e., the time between the infection of an infected and their subsequent transmissions. </p>

<P> Make the tab a different shade (light gray) and then this won't have parameters.   It will let us not have to explain SI every single time.  We'll expand the description later.</p>