title: How does R understand a multi level model?
body: <p>I'm new to MLM both in R and in general. I have a dataset of Building permits for a couple of cities and I have created a variable counting the number of parcels with a permit. Now, I want to perform a MLM to see if there is a census tract (a geographic level) effect going on. Here's where I hit a problem. When writing this line:</p>
  
  <pre><code>lmer(PERMITS ~ 1 + howeownership + (1 | CITY), data = dt2, REML = FALSE)
  </code></pre>
  
  <p>Do I need to also include census tract variable? If not, how would R know that my levels are CITY>>CT>>PERMITS (which is really the outcome)? </p>