Theory and Causal Hypotheses
Here's an example of a general theory: all members of Congress want to be reelected, so they will engage in specific activities like advertising, credit claiming, position taking to do so (Mayhew 1974).
Can you see the relationship here describing a political phenomena? All members of Congress want to be reelected, as in, they all want to stay in office. This is your dependent variable or the outcome you are interested in explaining. They will do this by advertising, credit claiming, and position taking - all of which are your independent variables or actions they will take to determine the outcome of the DV.
One way to think about developing a general theory is that it helps to have defined your concepts clearly to show the general relationship. Your operationalized definitions are used to develop causal hypotheses for testing, see below...
Now, the example and what you are doing is creating a general theory that explains the main outcome your are researching. You also need to begin to work on the causal hypotheses as well. What are the more specific ways you can measure and show this relationship at work? You can develop a separate causal hypothesis for each operationalized concept to your DV.
Back to the example: Our DV remains the same as our theory - members of Congress want reelection, so for shorthand, we will refer to our DV as reelection. But what about our IVs? There are 3, but in our theory they are in a general form, not operationalized. So let us begin with the first.
Advertising - operationalized means press coverage/interviews, speeches, campaign events
press coverage, speeches, public events ---> reelection (now each of our IVs and DV become something we find data to measure)
Credit Claiming - operationalized means policy expertise, pork spending, casework
policy expertise, pork barrel spending, casework ---> reelection
Position Taking - operationalized means public positions on the big issues of the day
Position on the issues of the day ---> reelection
In each one of our IVs we have moved from our general theory in order to develop a causal hypothesis for each one that can now be tested. Tested means that it is our way of collecting data to show how this happens. For example, we can go to a member of Congress's website or look at their newsletters or social media or how they vote on bills to determine what position they are taking on issues, so we can know what their position is. Right now we are not collecting the data, we are hypothesizing that each of these relationships are true and causal. Remember, a hypothesis is an educated guess inferred from your preliminary research and literature review.