title: Complex or several simple models must be used?
body: <p>I can't understand how models may be organised.</p>
  
  <p>I want try create some algorithms which helps analyze product name (description) and gets product properties (category, some parameters).</p>
  
  <p>I have tree structured data:</p>
  
  <pre><code>Category (name, null parent)
    |Category (name, parent)
      |Product (name+description)
        |Param(key-value)
        |Param(key-value)
        |Param(key-value)
        |...
  </code></pre>
  
  <p>I use model which will clasify top category for product, and after I use an other model which is trained on products which are belongs to the classified top category (so I can classify second level category). 
  For next step I use own models for every <code>param key</code> for <code>param value</code> classification</p>
  
  <p>In general, do I need a model for every leaf of my <code>tree structure</code> for next classification step?</p>
  
  <p>Are my thoughts right? </p>