There are several ways to strengthen your analysis. In addition, employing the methods discussed to achieve an accurate estimate of the reliability of your measure is also a good idea. Statistics Conclusion Validity relates to the statistical power of your study, and is the first type of validity to deal with in conducting any study - as it addresses the attempt to determine a relationship between your variables and your outcome. I'd like to focus a bit on statistical power.
Sample size is simply the number of people or units available to be studied.
Effect Size is simply the ability to detect an effect relative to the other factors that appear in your study. Alpha level refers to the likelihood that what you observed is due to chance rather than your program. Power is the likelihood that you will detect an effect from your program when it actually happens. For additional terms that are related to statistical inferences go to the Glossary of Terms. Finally, remember that the purpose of most research is to assess or explore relationships among a set of variables, and that the use of some straightforward, thought-out basic statistical methods can really enhance the strength of your findings.