title: Create balanced data set
body: <p>I am using R and have a long data set as the one outlined below:  </p>
  
  <pre><code>Date           ID     Status
  2014-10-01     12      1
  2015-04-01     12      1
  2015-07-01     12      1
  2015-09-01     12      1
  2015-11-01     12      0
  2016-01-01     12      0
  2016-05-01     12      0
  2016-08-01     12      1
  2017-03-01     12      1
  2017-05-01     12      1
  2014-10-01     13      1
  2015-04-01     13      1
  2015-07-01     13      0
  2015-11-01     14      0
  2016-01-01     14      0
  ...
  </code></pre>
  
  <p>My goal is to create a "balanced" data i.e. each ID should occur for each of the 10 dates. The variable "Status" for the initially non-occurring observations should be labeled as N/A. In other words, the outcome should look like this:</p>
  
  <pre><code>Date           ID     Status
  2014-10-01     12      1
  2015-04-01     12      1
  2015-07-01     12      1
  2015-09-01     12      1
  2015-11-01     12      0
  2016-01-01     12      0
  2016-05-01     12      0
  2016-08-01     12      1
  2017-03-01     12      1
  2017-05-01     12      1
  2014-10-01     13      1
  2015-04-01     13      1
  2015-07-01     13      N/A
  2015-09-01     13      N/A
  2015-11-01     13      N/A
  2016-01-01     13      N/A
  2016-05-01     13      N/A
  2016-08-01     13      N/A
  2017-03-01     13      N/A
  2017-05-01     13      N/A
  2014-10-01     14      N/A
  2015-04-01     14      N/A
  2015-07-01     14      N/A
  2015-09-01     14      N/A
  2015-11-01     14      0
  2016-01-01     14      0
  2016-05-01     14      N/A
  2016-08-01     14      N/A
  2017-03-01     14      N/A
  2017-05-01     14      N/A
  ...
  </code></pre>
  
  <p>Thank you for your help!</p>