Independent Variable and Dependent Variable
The current study seeks to assess the efficacy of PECS in the treating non-verbal individuals who suffer from autism. Specifically, the study seeks to compare effectiveness of PECS in promoting functional communication compared to the conventional methods for persons with autism. It also seeks to assess the conditions under which PECS is effective. Lastly, it seeks to compare the success rate of conversational speech between those who start using PEC at an early age and those who adopt at a later stage in life. Therefore, the independent variables are the educational program adopted (PECS and conventional teaching program), environmental factor and the time of adoption of PECS. The dependent variable is the functional communication skills of non-verbal persons with autism.
A quasi-experimental research design will be adopted for the present study. Previous studies have adopted a true experimental design. However, a true experimental design is costly since PEC has six phases. Therefore, the study would take years to implement. Besides, it would be costly. A quasi-experimental design imitates an experimental design. However, the key difference is that, unlike true experiments, the researcher cannot fully control potential confounding factors. The various measures that will be taken to minimize the threats of internal validity that arise due to the researchers lack of control will be discussed in the subsequent section.
Specifically, the study will use a non-equivalent group design Post-test Only. The design entails the use of naturally occurring groups in the study population, which in the researcher’s judgment mirrors a control as well as a treatment group (Trochim & Donnelly, 2008).
In comparing the functional communicational skills for PEC and other teaching programs, non-verbal persons with autism who are currently learning using the PEC system will constitute the treatment group while non-verbal persons with autism who are learning under other educational systems will form the control group.
In evaluating the success rate of those who start using PEC at an early stage, non-verbal persons with autism who started using PEC while they are less than years will form the treatment group while those who started using PEC after the age of ten will form the control group.
An exploratory analysis will be used to assess the conditions through which PEC is conductive. Given the qualitative nature of environmental learning factors, in depth interviews with instructors will be used to identify the common factors that impede or promote the effectiveness of PEC
Population and Sampling
The population of interest is non-verbal persons with autism. Recruitment of participants will occur at special needs schools. The study is interested in a unique segment of the population. Therefore, in special needs schools it is easier to recruit the study participants. Besides, it allows the researcher to implement a post-study design. A random sample will be selected from the population.
Measurement and Data Collection
Demographic information will be recorded for each participant including the age, gender, ethnicity and family income bracket. The functional communication skills will be measured using standardized tests for communicational skills. The tests will be graded and the data will be recorded in Excel. The data grades will be placed in the respective group: treatment and control group
Data Analysis
Descriptive statistics will be used to provide a demographic profile of the study participants. Frequency tables, measures of dispersion and central tendency will be applied.
A t-test for comparing two sample mean will be used to answer the study hypotheses. The study hypotheses that will be tested will be as follows;
H1: The mean functional communication scores for non-verbal persons with autism who are currently learning using the PEC system is higher that of non-verbal persons with autism who are learning under other educational systems.
H3: The mean functional communication scores for non-verbal persons with autism who started using PEC while they are less than years is higher than that of those who started using PEC after the age of ten will form the control group.
The hypotheses will be tested at 5 percent significance level.
There is no hypothesis for the second research question since an exploratory analysis will be used to answer the question.
Limitations of the Study.
As discussed in the earlier section, a quasi-experimental research design does not allow the researcher to fully control for competing explanations of the observed findings. Firstly, selection history threat may arise as the participants come from different backgrounds and have different personalities. Random sampling will be applied to minimize the selection history threat as the resulting sample will be assumed to be normally distributed. Selection mortality is also a potential threat given the disposition of the study participants. Some may refuse to take the tests. Random replacement will be used in case it arises.
Another key threat to internal validity is experimenter effect. The presence of the experimenter may influence the performance of the study participants in the test either positively or negatively. The instructors will be allowed to give out the tests as they are more familiar with them.
References
Trochim, W., & Donnelly, J. (2008). The Research Methods Knowledge Base. London: Cengage Learning.
Wadsworth. (2016). Quasi-Experiments. Retrieved from http://www.wadsworth.com: http://www.wadsworth.com/psychology_d/templates/student_resources/workshops/res_methd/non_exper/non_exper_03.html
