EBP FINAL

Mean values

Once the methods of are determined to be valid, next step is to determine if the results, potential benefits, or harms are important. Look at whether there is an association between specific treatments and outcomes or exposures and the condition of interest, then the strength of that association. The differences between groups in clinical trials are generally straightforward when expressed in terms of ———— —————

Proportions

Differences between groups in clinical trials are generally straight forward when expressed in terms of mean values. Results presented as ———————, such as relative risk reduction, absolute risk reduction, odds ratio, and numbers needed to treat (NNT), are more challenging to understand.

Absolute difference

————— difference is expressed as arithmetic difference between rates. Ex. 3% fewer patients in the new endodontic treatment group needed re-treatment. This represents the ————— difference or the arithmetic difference in rates. Between 6% and 3% (6% minus 3% is equal to a 3% decrease).

Relative difference

————— difference is expressed as a proportion of patients. Ex. The new endodontic treatment reduced the need for retreatment by 50%, i.e, the proportion of patients (percent increase or difference) in a group in whom the event is observed. (Starting at 6% and going to 3% cuts the numbers of individuals needing re-treatment in half).

Dichotomous

Outcomes are often ———————, either it occurs or it does not.

Contingency table

Tabular representation of categorical data. Comparison of proportions of results are presented in a 2x2 ——————— table.

Event rate

————— ————— is the proportion of patients in a group in whom the event is observed.

Control event rate (CER)

The —.—.—. Is the proportion of patients in the control group who experience the event. The formula for this is C/(C+D)

Experimental event rate (EER)

The —.—.—. Is the proportion of patients in the experimental group who experience the event. The formula for this is A/(A+B).

Risk ratio

Relative risk = ———— —————

Categorical

Nominal + ———————

relative risk (RR)

This indicates the likelihood that someone exposed to a risk factor (or treatment) will develop the disease (or experience a benefit) as compared to one who has not been exposed. This is expressed as the risk of the event in the exposed or experimental group, EER (A/(A+B)), divided by the risk of the event in the unexposed group, CER (C/(C+D)), or EER/CER.

>1 (more than 1)

An RR of —— means a person is estimated to be at an increased risk (or benefit).

<1 (less than 1)

An RR of —— means the person may be at a decreased risk (or benefit).

1

An RR of — means there is no apparent effect on risk or benefit.

RR (relative risk)

This is used to evaluate effectiveness of an intervention or the relationship between a risk factor and an outcome of interest. This can tell you if a relationship exists, and also how strong that relationship is.

Absolute risk reduction (ARR)

——————— ———— ——————— (———) or risk difference is the absolute arithmetic difference in the event rates between 2 groups. The formula for this calculation is C.(C+D) - A/(A+B), or CER - EER. The measure in this indicates the percentage of people who are spared the adverse outcome

Absolute risk reduction (ARR)

——— = untreated group disease risk - treated group disease risk

Relative risk (RR)

—— = treated group disease risk / untreated group disease risk.

Relative risk reduction (RRR)

——— = 1 - RR

Absolute

—————- risk reduction measures the amount of risk that is removed in the population actually measured as a result of having treatment or being exposed to a risk factor. ——— will vary depending on the baseline risk in a population.

Relative

—————- risk reduction is an ESTIMATE of baseline risk that is removed, based on the population being studied. The same ——— may represent different ARRs.

Odds ratio (OR)

The proportion of patients with the target event divided but the proportion without the event, which yields the ———— ————— of (A/B) / (C/D).

1

An OR of — indicates that the effects of the treatment are no different than those of the control treatment.

>1 (more than 1)

An OR of —— means that the exposure is associated with higher odds of the outcome.

<1 (less than 1)

An OR of —— means that exposure is associated with lower odds of the outcome.

Odds ratios (OR)

Overall effect of interventions — tells us whether or not an intervention works and how well it works.

RR (relative risk) and OR (odds ratio)

—— and —— measure the association between the dichotomous outcome and a predictor variable.

Relative risk (RR)

A —— tends to be calculated when the study design is prospective (participants are followed forward in time during the study). (OR or RR?)

Odds ratio (OR)

An —— is generally used when a retrospective study design is used. (OR or RR?)

OR

An —— compares the number of events to the number of non-events in each group.

Numbers needed to treat (NNT)

This reports the number of patients (or teeth, surfaces, periodontal pockets) that need to be treated with the experimental treatment or intervention to have one additional patient benefit or to prevent one adverse outcome. The lower this number is, the more beneficial/effective the treatment is.

Screening test

The objective of a ——————— test is to categorize individuals who are asymptomatic as being at high or low risk of a particular disease or condition, and not to make a definitive diagnosis.

Diagnostic test

The objective of a ——————— test is to establish an actual diagnosis and is often based on the presence of signs and/or symptoms of a condition or disease.

Sensitivity and specificity

Screening tests much have a high ——————— and ——————— in order for them to be useful. Ideally, they would both be 100% but that is impossible.

Sensitivity

——————— is the proportion of people with disease or condition who have a positive test (true positive).

Specificity

——————— is the proportion of people free of a disease who have a negative test (true negative).

Sensitivity

The formula for ——————— is A/(A+C)

Specificity

The formula for ——————— is D/(B+D)

Low sensitivity

A test with low ——————— will miss many cases of disease in a population, MORE FALSE NEGATIVES.

Low specificity

A test with low ——————— will subject many disease free people to additional diagnostic procedures, MORE FALSE POSITIVES.

Positive predictable values (PPV)

Proportion of people with a positive test who actually have the target disorder.

Negative predictive values (NPV)

Proportion of people with negative tests who do not the target disorder.

Low positive predictive value

A test that has a low ————— ——————— ———— in a population means that a large proportion of persons who test positively are actually false positives.

Positive likelihood ratio (+LR)

Sensitivity/1-specificity = this

Negative liklihood ratio (-LR)

1-sensitivity/specificity = this

+LR

The stronger this type of liklihood ratio is, the stronger the evidence for the presence or absence of disease.

5

Liklihood ratios above — are considered clinically useful and those above 10 are considered strong evidence to rule in a diagnosis of a disease.

0.1

Liklihood ratios below —.— are strong evidence to rule out the diagnosis of a disease.

Beginner

The first stage in the road to competence is ———————. You can understand the theory but cannot always connect it to practice.

Competent

The second stage in the road to competence is ———————. Can integrate theory with practice and demonstrate basic abilities of EBDM.

Proficient

The third stage in the road to competence is ———————. Can combine analytical thinking with intuitive experience with greater depth and breadth of understanding in a wide range of cases.

Expert

The final stage in the road to competence is ————— can effortlessly complete the EBDM process as normal easily incorporating each aspect into everyday practice while blending the highest level of judgement and skills.

Validity

The degree to which a study appropriately answers the question being asked or an instrument measures what it is supposed to measure.

Reliability

Refers to consistency of a set of measurements or a measuring instrument.

The consort statement

Protocol that guides the reporting of randomized trials by providing a 22-item checklist and a flowchart. An important research tool that takes an evidence based approach to improve the quality of reports of randomized trials.

Quorum statement checklist and flow diagram

This tool is used to improve the quality of reports of metal-analyses/SRs or randomized controlled trials. The checklist: is an 18 item checklist regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis. The flow diagram: provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials.

STARD/MOOSE

Criteria for improving reporting diagnostic studies to help judge for potential of bias and appraise applicability of findings. Standards for reporting diagnostic accuracy. Meta-analysis of observational studies in epidemiology.

Sampling bias

This refers to bias introduced if not all members of a population have an equal chance of being selected for a study. Consequently, the results of the study may not be generalizable to the entire population. Examples: pre-screening of a population for certain conditions before selecting participants, advertising for volunteers within a certain population, selecting only a certain ethnicity or gender.

Recall bias

Refers to bias introduced when asking a participant about their relevant history. Consequently, the answers that a participant gives may not be accurate. Ex: asking a person with lung cancer about events from 10 years into their past, may not recall events clearly or may assume that particular events are related to their condition when they are not.

Response bias

Refers to the bias introduced when a subject is being interviewed and gives the researcher the answers that they think they want to hear. Consequently, the results of the study may not be accurate. Ex. Study asking people about their oral hygiene routine at home-subject might indicate that they brush and floss more often than they really do.

Loss to follow up bias

Refers to bias introduced if not all subjects in a study make it to the end of the study. Consequently, the results of the study may be altered. Ex. Study of smokers to see if they develop lung cancer over 10 years. Subjects may move, pass a way, change habits, become uninterested in study. * required that at least 80% of cohort completes study in order for results to be considered valid.

Allocation bias

Refers to bias introduced if study subjects are not read only assigned to treatment or control groups. Consequently, the results of the study may not be generalizable to the entire population. Ex. If a researcher uses their judgement to place certain people into certain groups based on expected outcomes.

Measurement bias

Refers to bias introduced if researchers are not blinded to the treatment allocation in a study. Consequently, the results of the study may be skewed. Ex. Study of brand name toothpaste where researcher works for toothpaste company. May inflate results to make gains for their product.

Publication bias

Refers to bias introduced into a review if studies are not published because the results are not favourable in the eyes of the authors/investors. Consequently, review will have short comings.

Hawthorne effect

Refers to bias introduced when subjects are observed during routine tasks. Consequently, the results of the study may not be generalizable. Ex. Study of teenagers toothbrushing habits. If a researcher is observing the subject brush their teeth, they may brush for longer than they would normally.

Conflicts of interest

Refers to bias introduced if a study is funded by someone with a financial or other interest in the outcome of the study. Consequently, the results of the study may be skewed. Ex. Study of oral B electric toothbrushes funded by Oral B.

Small

For a study to be statistically significant, it means that there is a very ————— chance that the findings happened randomly.

P-value

Studies report statistical significance with a:

0.05

A p-value of —.—— means that there is only a 1 in 20 (5%) chance that the findings occurred by chance alone. The larger the study, the more likely to get a statistically significant result.

CONSORT, QUOROM, STARD, and MOOSE

To assist with the process, tools developed by evidence-based groups such as these 4 have been developed to critically appraise studies.

Description, prediction, explanation

Many researchers agree that the 3 goals of scientific research are:

Scientific communications

The transfer of scientific information from the point of discovery to potential users. Pathway occurs from scientists through dental professionals and then to clients. Responsibility of the dental information to be able to critically evaluate the quality of the new information form various sources to determine if the information should be incorporation into client care. The order is: scientists -> dental professionals -> clients.

Diffusion of innovations

The health educator uses this theory to describe the transfer of scientific information.

-scientists

- researchers

-industry

THEN

-publications

-presentations

-media

THEN

-practitioners: (pioneers, early adopters, middle adopters, late adopters).

There is a notable time lag occurring between the acquisition of new knowledge and when it becomes useable by public. Many people deprived of benefit of new information, sometimes for several years.

1. Industry, 2. Media, 3. Public, 4. Practitioners

The NEW path for diffusion of innovations is in this order:

Currently more companies/industries are tatrgering publ;if directly through the media in hopes they will relay information back to practitioners. Marketing strategy but also shortens time of diffusion. Puts greater pressure on practitioners to stay abreast of new info.

Literature review

The purpose of a ——————— ————— is to

1. Discover what is known and not known about the topic under review.

2. Purpose is the same for both researcher and consumers. Information uncovered from critical ————— of the ——————— contributes to the development, implementation, and results of the research study.

Title/author/contact information

What is the first part of a research article?

Abstract

What is the 2nd part of a research article? This is a summary of the research article. It provides an overview of the research, it's useful to determine if the article is relevant to the readers work. These typically follow a standard format: authors briefly state why the research is important, the methodology used, results, concluding statement based on the findings.

Introduction

What is the 3rd part of a research article? In this section the authors describe the rationale for the study, the author has reviewed the literature available on the subject and provides the reader with a summary of other research related to this topic. It also addresses questions that remain unanswered or require additional research. In general, this is also the section where the authors research proposal is introduced, and the hypotheses or anticipated results are stated.

Methods

What is the 4th part of a research article? In this section, the authors outline how the research was conducted. Key elements that the authors describe in this section include: participants in the study including the sample size and a description of those participants, how participants were selected for the study ( random, convenience, sample, census), what was measured and how was it measured, and an explanation of how the data was analyzed.

Results

What is the 5th part of a research article? In this section, the authors present the research findings. Any statistical analyses that the authors conducted are described as well. The results are often displayed using tables, charts, or figures along with a written explanation.

Discussion

What is the 6th part of a research article? In this section, the authors interpret the results. The authors may provide possible explanations for what they found, including an interpretation of unexpected results.

Conclusion/summary

What is the 7th part of a research article? In this section, the authors summarize what they found and link it back to the current literature in the area. Often, any limitations of the study are described in this section. The authors may also suggest directions for future research in this section.

References

What is the 8th part of a research article? Lists the publications that the authors cited in the article. The references may help the reader judge the quality of the article and be used to learn more about the topic area.

Literature review

A survey and discussion of the literature in a given area of study. It is a concise overview of what has been studied, argued, and established about a topic. It is a SECONDARY SOURCE. Presents the findings in an organized, concise manner, and is written in essay format. Must be organized around and related directly to the research question you are developing. Synthesize results into a summery of what is and is not known. Identify areas of controversy in the literature. Formulate questions that need further research.

Review

Introduction

In this section of the literature review, you include your background and PICO questions, or your reasons for doing the literature review. This part should also review the relevant literature, establish the need for the tidy and state the aim of the investigation.

Review

Methods

In this section of the literature review, you give sufficient details to allow the reader to understand how the investigation was conducted and to assess whether or not the aim was really tested. Brief section that outlines how you went about gathering the info.

Results/discussion

This section is the bulk of the literature review. Should present the results in sufficient detail to allow the readers to draw their own conclusions. The necessary statistics should be clearly presented without expressing any opinions of the author(s).

Conclusion

In this section of the literature review, it should include: what did you discover in a nutshell? Was your initial PICO question answered? Do you see a need for more or perhaps better quality research?

Variables

In the abstract of a literature review, make sure you identify your:

Variables

Parts or aspects of reality in research that can be seen to change or vary (temperature, speed, volume).

Hypothesis

Ideas put forward to be tested.

Null hypothesis

This statement says there is no relationship between phenomena.

Exploratory

This research method sets out to find out as much as possible. Ex. How much poverty is there with new immigrants? Do students gain or lose weight during an intensive program?

Descriptive

This research method is similar to exploratory. Once you determine how much poverty there is amongst new immigrants (for example), you now look at describing it in more detail.

Explanatory

This research method tries to explain why something is the way it is.

Quantitative

This type of data deals more with numbers. Emphasizes precise measurements (usually surveys or experiments). Less time consuming. Able to involve more participants.

Qualitative

This type of data has more detailed description of people's actions: interviewing techniques, observation, field work.