Internal Validity In Research

When it comes to external validity selection bias may be a threat. In external validity a researcher is trying to find a very generalized outcome that will apply to more than just the groups they are testing. If the subjects collected for the experiment are not randomly selected it opens up the threat of selection bias. For example, if a researcher designed an experiment to test the average IQ of a person but selected subjects from either a higher achieved or lower achieved group, the outcomes may not be representative of the entire population. Another situation that can cause different outcomes for external validity is testing.

(?) stated, “ confirmatory bias occurs when clinicians knowingly or unknowingly review patient information that can support but not counter their initial hypotheses” (p.28). When confirmatory bias is involved it can create inaccurate judgement. As well it can lead to overconfidence bias. Overconfidence can give a clinician the feeling that their judgement is more accurate than a clinician with no clinical experience.

Theory of planned behavior was designed to understand the relationship between attitudes and actual behavior when “theory of reasoned action” could not account for the behavior , such as health issues. Theory of planned behavior was an addition to the theory of action reasoned action that allowed for perceived behavioral control (Ajzen). Theory of planned behavior was intended to contradict the theory of reasoned action as studies showed behavioral intention did not always lead to behavior change (Ajzen). It is perceived behavioral control that becomes an interest in Random drug testing, because students have such a high amount of control in beating drug testing. In models such PDT and TRA “Theory of reasoned action” use should be deterred simply because of a consequence in the end, but theory planned behavior allows for control of other factors in random drug testing theory of planned behavior allows one explanation to the studies that indicate Random drug testing does not deter reported use, even though attitude does modify when the threat of Random drug testing behavior is

Example of speaking, If someone took a test of something once, would you get the same result if you took the test at a different time. That doesn’t mean that the test is testing what it thinks it is measuring. It might be better to means one attribute but actually capturing something else, but capturing that something else is reliably. It is often hard to know you are measuring the thing you think you are measuring exactly. Tranquilizing drugs that inhibit sympathetic nervous system activity often effectively reduce people 's subjective experience of intense anger or anxiety.

A supervisor may have higher standards than the company and use them in the appraisal, resulting in lower score. (Mondy,

Our results demonstrate that there is an ambiguity on the quality of the evidence in the psychotherapy field which in turn prevents the replicability. Standardised methodology, rigorous reporting policies and results from large RCTs could increase the quality of meta-analyses of psychotherapy and guide future efforts towards unbiased

While trying to please a specific stakeholder another holder could be compromised. For example, a patient may need a specific treatment. The physician’s administration attempt to gain approval form the insurance company to proceed with the treatment and is denied. The insurance company instead gives the physician another less expensive option. Though the option presented is less likely to give a better percentage of a positive outcome for the patient.

Nevertheless, stage-targeted activity promotion interventions are more likely to induce changes in motivation as well as short-term behavior changes. Therefore, more research must be conducted to study if interventions must go beyond health education, or incorporating environmental change strategies to improve opportunities for physical activity. Commentary 2 Adams and White (Adams and White, 2004) offer five reasons why stage-based interventions to promote physical activity may not work. The problem of appropriately classifying individuals into stage as noted by Adams and White (Adams and White, 2004) may be part of a more general problem of the validity of the stages identified in the TTM. Commentary 3 Adams and White appear reluctant to condemn the TTM because a physical activity intervention is very difficult to determine.

An individual form its subjective judgement of opinion and ability in comparison with other individuals. If there are group differences between individuals, it has been shown that their behaviour will change in order to alter the situation and minimise those differences between individuals. Actions taken to reduce discrepancies in opinion are rather uncomplicated to uniform in comparison to the case of abilities where two conflicting forces are present. The first forces action to reduce the discrepancy but the other is the willingness to do better and better, which results in the failure of reaching a uniform and a social steady state. This is demonstrated in competitive behaviour, actions to protect dominance and in different types of cooperative behaviour (Festinger, 1954, pp.9).

The effect of these factors on data missing cannot be overlooked because evidence from past studies have shown that demographic differences of study participants affects the validity of study results and findings(Goldberg et al. 2001; Galea & Tracy 2007c). This literature review is aimed at examining factors that could influence non-response and continued participation of samples in cohort studies. It will highlight the impact of sociodemographic characteristics of subjects on missing data and study quality. Morse so, with the declining participation rate, the review will attempt to address the issues bordering participation of different groups of subjects and how these could be addressed, accommodated or adjusted in study design, planning and data