Independent Intervening and Dependent Variables-OMG what a confusing concept!

I'm looking to find the independent, dependent and intervening variables of my study so I can develop some good research questions.  This chapter was rather confusing and mapping out the different variables was a bit difficult.  Here's what I've come up with so far, but are they right??

The purpose of my study is do identify the interventions and service delivery methods used in southeastern Pennsylvania School Districts to reduce SLP caseload numbers to provide effective treatment of communication disorders in the least restrictive environment.

Independent                             Intervening                                                             Dependent
caseload size                           pre-evaluation intervention tools                          actual intervention/service                        
                                                                                                                            delivery

# responsibilities                      time to deliver interventions                                 effectiveness of
                                                                                                                             intervention
                                 

collaboration/training               barriers to service delivery methods                     perspectives of            
                                                                                                                             collaborating staff

Theoretical Perspective

I think that my topic/problem fits well with the sociocultural theory by Vygotsky (1978).  This theory is an educational based theory that looks at how a child learns.  Vygotsky's theory states that one learns by using psychological tools (signs, symbols, texts etc.) to internalize information, which  helps the individual to master functions of perception, memory, attention and others (Kozulin, Gindis, Ageyev, & Miller, 2003).    These authors stated that a child's development of higher mental processes depend upon mediating agents that interact within that child's environment.  There are human and symbolic mediators which direct the child who takes in the information and adds it to their internal thought processes (Kozulin et al., 2003).

Kozulin, A., Gindis, B., Ageyev, V. S., & Miller, S. M. (2003).  Vygotsky’s educational theory in cultural context.  Cambridge University Press: Cambridge, UK.  Retrieved from: http://books.google.com/books?hl=en&lr=&id=mfCHutwHT-cC&oi=fnd&pg=PR11&dq=Vygotsky%27s+educational+theory+cultural+context&ots=ufpWqhjYqD&sig=1PytMWBqaA66yYkEMjAa2WpsYNY#v=onepage&q=Vygotsky’s%20educational%20theory%20cultural%20context&f=false

Research Literature Map

Here is a copy of my Literature Map minus the Theoretical Perspective which I am still searching for.  When I find out what theoretical perspective my dissertation will follow I will post that.  That is the worst part of the literature review to date for me.