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Yacca Library NWHHS: Step 2: Acquire

Yacca Library is the Medical Library for the North West Hospital and Health Service (NWHHS).

Having the right skills and knowledge to find appropriate evidence and literature, to inform a change in practice, will save you time and empower you to find evidence when needed.

Find the best evidence to answer your question

Before you start searching for information it’s useful to know the type of information you should actually be looking for. To determine this, you need to consider the ‘type’ of question you're asking. This is because certain types of questions lend themselves to certain types of research studies. Therefore if you look for research which matches your question type you will find far more relevant evidence. Let’s take a look at this table to explore this further.

Therapy / Intervention Testing the efficacy of drugs, surgical procedures, or service delivery Randomized Controlled Trial (RCT)
Diagnosis / Screening Testing the validity of diagnostic or mass screening tests Cross sectional study
Prognosis Determining the likely course of a disease or condition     Cohort or longitudinal study
Etiology / Causation Determining if a harmful factor is related to the development of an illness

Cohort study or case-controlled study

Case report for a rare illness

Prevention Determining how to reduce the chance of disease by identifying and reducing risk factors, and how to achieve early diagnosis by screening RCT or cohort study or case-controlled study
Cost analysis Comparing the cost and consequences of different treatments and tests Economic analysis
Point of view Patient or staff experiences or concerns Qualitative study

Systematic reviews are also useful for all of these!

Consider our resistant vs. ordinary starch question, what type of question is it? Review the table above and think about which type of question it might be.

We could identify this question as a therapy question because we are determining the effect of an intervention on patients.  Therefore, looking at Randomized Controlled Trials would be helpful for finding evidence to help answer our query. However, it's good to remember that your question may be a combination of question types, it will not always fit neatly into one category.

Are you familiar with the differences between study designs? Brush up on your knowledge by watching the videos below. This will help you to build a picture of the different study designs you will be looking for based on your question type.

Learn more about Systematic Reviews

Learn more about RCTs

Cross sectional studies

Cross-sectional studies are conducted in a specific time period which does not contain follow-up and asks “what is happening in a specific time period?”. These studies try to explain potential causal associations between causes (exposures) and outcome (disease or clinical outcome).

Take a look at the example below to understand more about this study design.

You can read the full article by clicking on the image.

Learn more about cohort and case control studies

Case reports

Case report / case series studies is a report on a single patient, or a series of patients, with an outcome of interest and are prepared for illustrating novel, unusual, or atypical features identified in patients in medical practice.













The example here is taken from a science news website discussing a case report of a unusual outcome as a result of a stroke.

You can read the original research article by clicking on the image.

Hierarchy of evidence

In EBP,  all of these study designs are ranked in terms of quality. There are variations on the hierarchy of evidence that you  will come across however the principle is the same - some research studies have less bias than others and are more reliable.

Watch the video below to learn more about the hierarchy.

Think about your project, what type of question are you asking and what study design best matches your type of question?

How do I know which studies have those specific study designs?

When you begin to search for studies you might be wondering where and how you can identify the study design of the articles you're consulting.

You may be wondering well, how do I find those specific study designs?

1. The type of study is usually clear in the title or abstract
2. Use the type of study design you’re looking for in your search. E.g., diabetes AND “cohort study”

3. Use filters available in some databases such as the RCT filter available in CINAHL
4. Go to specific databases like Cochrane Reviews which specialises in systematic reviews


Boolean operators

Searching tips #1

As you begin to search for information, it's good to know how to effectively search databases such as CINAHL or Medline.

These types of databases will not respond if you type out sentences or natural language (like a Google search does).

When searching databases, you get the best results when you use Boolean operators to structure your search.

Let’s take a look at the operators which you can use in your search strings

AND is used between terms to narrow your search:

Smoking AND cancer

will retrieve results containing both search terms

OR is used between terms to broaden your search

Dementia OR Alzheimer’s

will retrieve results containing either search term

NOT will omit a term from your search

Nausea NOT chemotherapy

will retrieve results containing the word nausea but not the term chemotherapy.

Other tips

Searching Tips #2

In addition to Boolean operators, there are also some functions that help to retrieve search results more efficiently.

The * is particularly useful for words that could have multiple endings or spellings and you want to retrieve variations on a word or capture both Australian and American spellings of a word.

Use the * to save time and increase results for variations on a word.

E.g., diabet* will retrieve diabetes, diabetic

“ “ will search for phrases rather than single words. If you were searching for pressure ulcer without the “ “ you would retrieve results for pressure AND ulcer as single words found in articles.

Use “ “ around two words to retrieve the terms as a phrase, e.g., “pressure ulcer” will retrieve results that contain the terms next to each other in that exact order.

Search strings

Do you remember that key word table from earlier? This is where it becomes important. Let’s take our searching tips and apply these using the keywords from the table.

(P)   Middle aged women (P)   overweight (I)   resistant starch (C)   ordinary starch (O)   weight loss
women obese R.S starch thinness
female body size dietary fibre  
middle age     dietary carbohydrates  

A simple search statement may be “weight loss” AND “resistant starch”, which captures two parts of our PICO question. However as you can see in the second more complex search statement, additional boolean operators help us to include all aspects of our PICO question.

1. “weight loss” AND “resistant starch”

The above search statement combines two of our concepts, but when we want to add in other synonyms we need to use brackets to enclose our different terms. See below.

2. (overweight OR obes*) AND “middle aged” AND (“resistant starch” OR R.S. OR “ordinary starch”) AND “weight loss”

This search will retrieve more results than with the simpler search string, as we're providing the database with more options for words to look for.

Made with Padlet

Where should I search?

Now that you have your search strings ready, you might be wondering where you should start looking for information.

CKN is available 24/7 and is a great place to start searching for high quality information, always go here before searching on the open web.

Sign up for a CKN account so you can access it at home and explore some of the features.

Google Scholar

Searching with Google Scholar



You can link up CKN and add any universities affiliations you may have logins for to Google Scholar in order to get the full free text of an article. Always click 'Find it @ CKN' to get access to the free version. Don't make the mistake of clicking on the title of an article as they will ask you for money to access the paper!

Google Scholar is a useful tool to use, but we advise to use it second to CKN and be critical of the results you may find. Why? There is no quality control – no peer review filter. Google scholar draws on articles from anywhere and everywhere. You need to apply a thorough evaluation of the article before using anything from Google Scholar.

Hover over the title 'Tackling Evidence Based Practice' at the top of the screen and click on 'Step 3: Appraise' to finish working through the guide.