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## Research Methods

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**Research Methods**• in Marriage and Family Therapy • University of Guelph, Open Learning and Educational Support**Today**• This Journal Has 22 Minutes • Clinical Trials • Meta-Analysis • Correlation & Prediction**RAT Scores Day Three**• Scores ranged between 25 – 34 • Mean score was 29.89 (1- 30.67; 2- 28.67) • SD was 3,81 (1 - 3.94; 2 - 3.71) • 68.26% of scores fall between 26.08 and 33.70 • 95.44% of scores fall between 22.27 and 37.51**Advantages to Numbers**• Easier to collect and score • Easier to determine improvement or decline • “Objective” = believable**Disadvantages to Numbers**• What do they mean? • Are they really believable? • Were you just being nice?**RandomizedClinical Trials**• Considered by many to be the “gold standard” of research • Almost necessary to show efficacy and effectiveness of treatment • Based on experimental design methodology**RandomizedClinical Trials**• Goal: compare a treatment group to a control group to determine difference in outcome • Assumes that one will be better than the other and lead to better outcomes • Most restrictive form of clinical trials • High control over extraneous variables**RandomizedClinical Trials**• Three basic elements: • Intervention and control treatment • Outcome measures • Randomization**RCTs & Research Questions**• Three possible questions: • Is X an efficacious treatment of _____ ? • Is X an effective treatment of _____ ? • Is intervention A more effective than intervention B in the treatment of ____ ?**Definitions**• Efficacy: How a treatment works in ideal circumstances, when delivered to selected patients by providers most skilled at providing it (usually relates to strict criteria of RCTs) • Effectiveness: How a treatment works under ordinary conditions by the average practitioner and delivery system for the typical patient • (Lyness, Walsh & Sprenkle, p. 302)**Random Sampling**• Ensures that each person in the population has an equal chance of being selected • Easier to justify statistically any generalizations made to a larger population**Random Selection**• Ensures participants have equal opportunity to be in either treatment or control group • Limits bias of allocation to a group • Produces comparable groups for testing • Validating statistical tests of significance (similar or equal size) • Matching should only be used with small sample sizes**Sampling Biases**• Allocation – when assignment influenced by investigator’s knowledge of treatment • Response – when participants know what group they are in • Assessment – when staff members know what group participants are in • Double-blind study is best but near impossible**Variables**• Independent – manipulated by researcher to produce outcomes (ie. Intervention) • Dependent – the outcome measures that should be affected by changes in the treatment • Supplementary (nuisance) – need to be controlled to prevent interference in interpreting group differences; can be controlled for statistically or by blocking**Therapist Variables**• Effectiveness – differences in the abilities of therapists • Allegiance – commitment to or belief in the treatment • Use the same therapist, match on allegiance and effectiveness, or perform statistical analyses to see if therapists differ significantly**Ethical Considerations**• Voluntary participation, informed consent • Do no harm • Anonymity, confidentiality**Withholding Treatment**• Is it unethical to put clients in a control group where they do not receive treatment?**Alternatives toNo Treatment**• Wait list • Treatment on demand • Parallel treatment group or add-on**Data Collection**• Stored in a secure location, limited access • All data files on computer should be password protected • No identifying information attached to the data**Clinically Significant Change**• Not enough to say that the experimental group has improved • As defined by Jacobson & Traux (1991):“the level of functioning subsequent to therapy places that client closer to the mean of the functional population than it does to the mean of the dysfunctional population”**Strengths of RCTs**• Can demonstrate the efficacy and effectiveness of interventions • Can determine comparisons between interventions • Political and economic implications of manualized treatment and evidence-based practice**Weaknesses of RCTs**• Costly and time-intensive • Demonstrate efficacy but not always effectiveness • Promotes homogeneity of treatment for problems that are not typically homogeneous • Contrast with findings of common factors research**Everything you ever wanted to know...**• http://www.statsoft.com/textbook/**Studying the world**• Variables (things you measure) • Experiment: do something and see what happens • Correlation: observe the world and see how things are related**Types of Variables**• Nominal - names, no order (Carl, William, Robert; male, female; single, married, divorced) • Ordinal - order, no interval (small, medium, large) • Interval - order, interval, no zero point (degrees C) • Ratio - order, interval and zero (degrees K, age, height, DAS score)**Variables in Experiments**• Independent - the ones you manipulate • e.g. EFT • Dependent - the results • e.g. Marital satisfaction**Making sense of the numbers (interval, ratio)**• If you take several measurements of the same thing, you tend to get the same result (central tendency)**“Most people agree that Carl is a great guy. Some think**that he is superlative. Some think that he is not so hot.” Frequency Value**Mean**• Me after ten p.m. • Measure of central tendency**Mean**Example: 12 students complete the RAT Their scores range from 23 to 32 The sum of all the scores divided by the number of scores = 27.9 This is the mean x = ∑x n The mean is a measure of central tendency**Standard Deviation**This is a measure of the spread of the individual values away from the mean A large standard deviation means a lot of variation in the results A small standard deviation means that the mean is fairly representative of the value of the variable for that population**Calculating Standard Deviation**• Calculate the mean • Measure the difference of each value from the mean • Square the differences to get rid of the negatives • Find the mean of the squared differences • Take the square root**Standard Error**σ/√n Standard Deviation divided by the square root of the number of observations 95% confidence interval**Type I Error**• α or false positive = thinking there is an effect when there is none**Type II error**• β or false negative = thinking there is no effect of treatment when in fact there is**Statistical terms**• efficacy: capacity to produce an effect (ideal) • effectiveness: change under real-life conditions**Mode**• a) ice cream • b) the most frequently occurring value