The Study Design

A research study design is a plan made by the researcher which incorporates all methodological decisions that will be adopted during the research process and that will outline the strategies that will be applied to create well organized, accurate and interpretable results (Polit and Beck, 2010). Research design as a part of a quantitative approach usually involves decisions about such issues as whether any intervention or comparison will be made, the type of setting that the data collection will take place within, the number of data collection sessions, and any plan to control the external variables (Polit and Beck, 2010).

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A) Study One: A non-experimental cross sectional point- prevalence study.

B) Study two: An experimental prospective longitudinal descriptive correlation cohort study.

Although experimental designs are generally much preferred over other designs in quantitative studies, due to their ability to infer causal relationships, to limit bias through randomization and to control external variables (Polit and Beck, 2010), they are still not applicable to all types of quantitative research.

In this thesis both experimental (incidence study) and non-experimental (prevalence study) designs were used for the following reasons:

- The independent variables (risk factors for PU development) could not be manipulated. Risk factors could be a medical problem or a health condition, such as oedema or obesity amongst others, which could not be changed or unethical to be held such as using sedative or inotropic medications, or the use of some medical equipment such as oxygen probs.

- Experimental design was appropriate for answering the research questions related to the prediction of the two scales performance (ability of the Glamorgan and Braden Q RASs to detect risk in critically ill Jordanian children).

- A descriptive correlation design was more appropriate for investigating the relationship between all identified risk factors and the development of PU because this study is interested in describing the relationship between independent and dependent variables without seeking to establish a causal connection. Otherwise, as mentioned previously, it was unethical and impractical to manipulate independent variables (predicting factors).

- This study is interested in observing the phenomenon (PU development), and describing its different aspects (size of the problem at one point and through time by measuring incidence and prevalence, staging of PU and describing the Glamorgan RAS

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in terms of its ability to detect risk of the phenomena in the same population as compared to the Braden Q RAS).

However, there are several disadvantages to using the non-experimental design, the major two being its inability to reveal causal relationships between variables, and the bias created by self-selection. Many nursing studies depend on correlation studies rather than those which seek causal relationships because of the nature of most nursing problems, which are not amenable to experimentation.

Also, the non-experimental design is thought to be more efficient in collecting a large amount of data on one specific problem (Polit and Beck, 2010). In this study, a large amount of data was sought to clearly explore the PU problem in the selected population and to clearly identify significant predictors of PU development in paediatrics, because of a scarcity of such data in this particular population compared with adults.

Self-selection is another negative aspect of conducting a non-experimental study. If the researcher does not randomly select subjects but they are instead chosen for their unique features, this may cause bias in interpreting findings. In such cases, any difference between studied subjects, by chance only, could be a possible explanation of some results rather than the existence of an actual relationship between variables.

For the incidence study of this research work, all the critically ill children who achieved the required number of assessments (not less than two) were included. No specific characteristics were sought and no specific conditions or diagnoses were followed, so as to decrease the bias of the non-randomisation in the sample selection as much as possible. The nature of the study required patients to be assessed more than once (more than the initial assessment) to allow time for the outcome to be accurately detected (PU development). In the prevalence study, however, all children who were inpatients on the day of study, and who matched the inclusion criteria, were included in the survey.

3.3.3.1 Study One: The Cross-Sectional Point-Prevalence Study

Cross-sectional design involves collecting data at one point in time, or multiple points over a short period of time (Polit and Beck, 2010). It was used in this study to collect

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data about PU in children across all wards in one hospital in Jordan. The data was collected in one day for all inpatients. This design was appropriate for answering the research question regarding the size of the PU problem among paediatric inpatients in Jordan. It allowed the percentage of affected children at one point in time to be calculated, their characteristics to be described, and the categories of patients’ PUs, their sites and their numbers, as well as their original source (either surface or device related ulcers) to be identified.

This design was also thought to be more economically effective and easier for the researcher in terms of managing the data collection and analysis. In addition, it is the most commonly used design in prevalence studies, as mentioned in the literature review chapter.

The shortcoming of this design is the inability to infer results related to changes over time in the studied variables, because these changes might be the result of other external variables such as social or technological factors. However, in this part of the thesis, there was no attempt to infer any relations between the studied variables and the development of PU. The data collected were descriptive in nature, used to describe the characteristics of patients, both those who had PU and who were found free of ulcers on the day of the study. Also, a description of the admission wards was included.

3.3.3.2 Study Two: Non-Experimental Prospective Longitudinal Descriptive Correlation Cohort Study.

A longitudinal study aims to collect data at multiple points in time over an extended period (Polit and Beck, 2010). This design is used to help investigate processes that evolve over time, or to study a phenomenon in which the time consequence is important, in order to compare between two groups of subjects (after intervention, for example). In addition, such a design could enhance the research control, as collecting data before intervention can help the researcher establish initial group differences. In this study, a longitudinal design was required to examine PU development, which is a medical condition that evolves over time and also to compare the Glamorgan RAS with the Braden Q Scale in terms of the ability of each to predict paediatric patients’ risk of

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PU development; these children and neonates needed to be followed over time after completing the initial RAS’s risk classification.

A prospective correlation design was used to help establish a link between the presumed causes (risk factors / predictors) and the presumed effect (PU development). Also, the prospective design was helpful in measuring the incidence of PU development among critically ill children, because it is a time related problem, and in the follow-up of ulcer- free children, to see if they would develop the problem over time or not.

Initial assessment of ulcer-free children in the critical units was carried out in order to classify children according to their risk score based on the Glamorgan and the Braden Q RASs. Subsequently, a follow up of all assessed children was conducted to identify children who did actually develop PU during the study period. This feature of the prospective design has enabled the researcher to describe the predictive ability of the two scales within the studied population.

Other designs which entail a restricted study time period, such as the cross-sectional design, would not have been useful for answering the related research questions, because of their inability to detect relationships between variables (Polit and Beck, 2010). Prospective design is more costly than the retrospective design, but thought to be stronger as it clarifies the conflict regarding the sequence of cause and effect. For example, this study included an initial collection of data on the assumed contributing factors among ulcer-free subjects, who were then followed over time (8 weeks), and assessed for the outcome, PU development. There was no doubt, therefore, that, any identified risk factors had preceded PU development and not vice versa.

However, the existence of a correlation between variables is not enough evidence that the independent factor causes the dependent outcome (causative relationship), even if the relationship is strong (Polit and Beck, 2010). For example, based on several univariate and multivariate statistical analyses, the results of this study indicated that some factors, such as age being less than one year and a longer length of stay in ICU, had contributed to the development of PU. However, it would be inaccurate to say that these factors had caused the occurrence of PU in this group of critically ill patients,

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even though they proved to be significant statistically. This is because, in such non- experimental correlation designs, the effects of other covariates cannot be controlled, also, a randomised assignment of sample cannot be established (Polit and Beck, 2010).