assesses the degree to which the design illustrates casual direction between the predictor

and outcome variables. Case studies sometime have low internal validity because they,

unlike experimental designs, do not create interventions to create control and treatment

groups. The retrospective nature of the case selection threatens the internal validity.

However, I took certain measures to increase internal validity.

 I address this concern by evaluating multiple cases, creating comparison groups,

assessing linkages through several instruments and data sources and using an idiographic

approach to examine cases. I reduced the number of possible alternative causal

explanations by comparing multiple cases. I created comparison groups based on the

outcome variable and compared them to each other, based on the predictor variables. The

use of comparison groups and their contribution to internal validity is comparable to

experimental designs, except in case study designs the groups are created posteriori. I

examined how different predictor variables affect multiple cases within each comparison

group. This inferred causality.

 "Idiographic explanation focuses on particular events, or cases, and seeks to

develop a complete explanation of each case. By developing a full, well-rounded causal

account, case studies can achieve high internal validity" (de Vaus, 2001, p. 233-234).

Unlike nomothetic explanations, which focus on a restricted range of variables, the

idiographic approach decreases the possibility of alternative explanations and offers a

fuller explanation of each case. I assessed the interrelation between the variables by

measuring numerous predictor variables in combination with each other (de Vaus, 2001).

 Further, I include a historical context of Indian agricultural policy and Cherokee

agriculture to decrease the effects of history and examine how history may influence

behavior. I reduce the effects of maturation by including questions within the instrument