Introduction
Considering the matters of the threats for the internal validity, it should be stated that the necessity to analyze all the possible threats and aspects, which violate the validity, is originated by the issues of the scientific researches, and the matters of the inferences made based on the scientific experiments.
Key Threats of the Internal Validity
The key threats of the experimental validity may be grouped under the key features and origins of the threats. The most universal is the following seven threats:
- History (delays the outline of the results, thus, the evidence of any occasion that may influence the set of results may increase)
- Maturation (increases the influence of the environmental factors)
- Testing (provides the threats of non-precise measurement of the results)
- Instrumentation (considering the fact, that measurements may be done in different ways every time, and the errors may be changing, the threats are evident)
- (Statistical) regression (this factor does not include the possibility of exclusions from the general statistical rules)
- Selection (the observed differences may occur as a result of the differential application of the research requirements)
- Experimental mortality (these are the differential drop-outs of some results, closely linked with)
To avoid these threats, precise measurements, accurate and unbiased selection as well as simple and similar approaches should be applied within every particular experiment.
Originally, every threat has its origin; nevertheless, the most dangerous is the bias (which is associated with Selection) and the changes of the Instrumentation. Considering the origins of the other threats, the regression and selection are not so violating, as the interference of hypotheses may cause the origination of a new issue, nevertheless, these can be separated at any moment.
Considering the examples from the landscape architecture sphere, the threats for the internal validity may be the following
- Landscape architecture is developing slowly, consequently, it is hard to observe the influence of the history threat. Any attempt to describe it fails.
- The tastes and professional habits of the architects change over time, consequently, the researches will not be effective, if delayed essentially.
- In the research by Rogers (2005), it is emphasized that long-term impact may cause inaccuracies in measuring the watershed parameters, consequently, the testing threat is evident.
- Under the research instruments, used by Rogers (2005), it should be emphasized that long-term researches are impossible without changing the instruments, or at least the approaches of measuring. (as in Michael, 2001)
- Because exclusions are not obvious in landscape architecture, the researchers fail in describing these threats.
- It is the most evident threat, as landscapes always differ from each other, and it is impossible to do without this threat. (as in Lange and Schaeffer, 2001)
- similar issues have been already described in history and instrumentation parts.
On the other hand, the awareness of the threat may bolster the entire set of results in any research. Thus, considering the issues, studied in the “Long-term impact of development on a watershed” (Rogers and Buren, 2005) study, it should be emphasized that “Instrument Changing” threat is observed here, nevertheless, considering this fact, it is possible to find the real values of the research, and minimize the consequences of the possible threat. Thus, the professional researcher will not be misled by these threats.
Conclusion
Finally, it should be emphasized that the threats of internal validity are closely associated with the matters of non-professional approaches towards research. Originally, there are several approaches towards classifying these threats, nevertheless, the seven main threats have been outlined and analyzed. On the one hand, these threats may violate and distort the results of the entire study, on the other hand, they may originate a quite new hypothesis. Nevertheless, the consequences of the threats depend on the approach and the general awareness of the matters of the research and the threats in general.
Works Cited
Lange, Eckart., Schaeffer, Peter. “A Comment on the Market Value of a Room with a View” Landscape and Urban Planning Vol. 55, 2001, pp. 113-120.
Michael, Sean., Hull, Bruce “Environmental Factors Influencing Auto Burglary” Environment and Behavior, Vol. 33 No. 3, 2001 368-388. Sage Publications, Inc.
Rogers, George., Buren DeFee “Long-term impact of development on a watershed: early indicators of future problems” Landscape and Urban Planning, 2005 science direct. Elsevier B.V. Publishing.