Presentation is loading. Please wait.

Presentation is loading. Please wait.

LECTURE 3: DATABASE SEARCHING PRINCIPLES

Similar presentations


Presentation on theme: "LECTURE 3: DATABASE SEARCHING PRINCIPLES"— Presentation transcript:

1 LECTURE 3: DATABASE SEARCHING PRINCIPLES
COMMUNICATION SKILLS 101 LECTURE 3: DATABASE SEARCHING PRINCIPLES AND PRACTICALS LEVEL : DATE 20/09/16 Lecturer: G. Kadyamatimba

2 Introduction “Looking for or trying to find a needle in a haystack, “ is an English idiom which means looking for something that is extremely difficult or impossible to find especially because the area you have to search is too large.( Cambridge Advanced Learner’s Dictionary and Thesaurus)

3 Introduction Does this idiom have any applicability in the information landscape we have been trying to navigate in the last few weeks??? There is a lot of information out there One needs information literacy skills to get the needed information

4 Presentation Layout Introduction Presentation Layout
Learning Objectives Database Searching Demonstrations ( Ebscohost) Searching in Google Searching in Google Scholar Evaluation of search strategies Conclusion References Evaluation

5 Learning Objectives By the end of the lecture students should be able to : Formulate search strings using Descriptors/ Keywords/Content/ Subject words Boolean Operators AND, OR and NOT Synonyms Truncation Wild cards

6 Learning objectives cont...
Field searching Phrase Searching Proximity Operators Execute the search strings in the Ebscohost database, Google and Google Scholar Compare the results of searches from the different databases Evaluate search strategies using precision and recall

7 Formulation of search strings
Examine the relationship between higher education expansion and technology adoption and usage in Zimbabwe. What are the keywords? What are the concepts? Are there any stop words? What are the synonyms?

8 Searching in Ebscohost
Ebscohost is a powerful online reference service available through the internet, which provides access to hundreds of proprietary full text and popular databases from leading information providers.

9 Boolean Operators higher education AND technology
higher education AND technology adoption higher education AND technology AND adoption AND usage (higher OR college OR university) AND education AND technology

10 Boolean Operators Higher OR college OR university AND technology adoption (Higher OR college OR university) AND technology adoption (Higher education OR university) NOT college AND technology adoption Add Zimbabwe to all your search terms and see what happens

11 Truncation Can expand a search
Higher educat* AND technolog* AND adopt* Wildcards Take care of spelling variations eg colo#r or odo?r The symbol is a # or a ?

12 Phrase searching Indicated by quotation marks
Eg “ technology adoption and usage” Returns results with the words in the exact same order Exercise What are proximity operators and how do they function

13 Field Searching Higher education in the title field
Higher education in the subject field If author is known one can search the author field for publications by a certain author eg Mpofu in the author field.

14 Google Google is a powerful search engine that uses crawlers or spiders to search the web. A google search will retrieve anything from citations, full text articles, pictures, blogs to objects etc It uses natural language to search the web.

15 Google Scholar What is Google Scholar?
It is a scholarly citation (bliographic) database, an attempt to provide free citations to scholarly publications that are typically "fee-based". 

16 Google Scholar What is included in Google Scholar?
Google Scholar's database indexes items Google considers "scholarly," including articles, theses, books, preprints, abstracts, conference proceedings, and technical reports.

17 Google Scholar What is NOT included?
It is difficult to determine how much of the scholarly literature is included in the database, but only a portion of the literature of any discipline is indexed in Google Scholar. Great for getting started in an area,

18 Exercises Repeat the search strings you used in Ebscohost in Google and Google Scholar Note the differences in the results

19 Evaluation of search strategies

20 Evaluation of search strategies

21 Recall RECALL is the ratio of the number of relevant records retrieved to the total number of relevant records in the database. It is expressed as a percentage as follows:

22 Recall

23 Precision PRECISION is the ratio of the number of relevant records retrieved to the total number of irrelevant and relevant records retrieved. It is usually expressed as a percentage as follows.

24 Precision

25 Precision and Recall Precision and recall are inversely proportional.
In other words , the higher the precision the lower the number of records retrieved( recall). The higher the recall, the lower the number of relevant items retrieved (precision). The various search strategies affect precision and recall and they need to be continually improved until satisfactory results are retrieved

26 Exercise A database has 10 000 records
You conduct a search and it retrieves 1000 relevant records It leaves behind 2000 relevant records The search retrieves 3000 irrelevant records Calculate the precision and the recall

27 Conclusion Looking for information in today’s information society is indeed like looking for a needle in a haystack. But by using the right search strategies the needle can be found.

28 References MIT Libraries : Database Search Tips
Available from Accessed 19/09/16 2. Database Searching Recall and Precision (pdf)

29 Evaluation There were challenges with manipulating the database, but otherwise the learning objectives were achieved. Students learnt about various search strategies. Evaluation of search strategies could not be done due to time constraints.


Download ppt "LECTURE 3: DATABASE SEARCHING PRINCIPLES"

Similar presentations


Ads by Google