Describe the purpose of analysis
Evaluate different fact finding techniques: interviews, questionnaires, observation and document sampling
Distinguish between functional and non-functional user requirements
Explain the purpose of a data flow diagram (DFD)
Produce context and level one DFDs for simple scenarios
The main purpose of analysis is to investigate a problem(s) with an information system. The solution to the problem can be either improvements within the existing system or creation a new information system. The systems analyst(s) who will be investigating the current system (carrying out the analysis), may have little or no knowledge of how the existing organisation works.
Evaluating Fact Finding Techniques
In order to carry out a full investigation a method(s) of fact finding are employed.
This involves the users answering questions from the system analyst on a one-to-one basis or in small groups. The interview can be with current or potential users and is undertaken to find out their requirements, problems and opinions. This is the most common method. The user can express their opinions in a detailed way. The interview may be structured or unstructured allowing questions to be followed up.
Excellent for personal contact and understanding with the user
Can elicit hard-to-quantify information and knowledge and extra detail can be drawn out on the spot
Opinions can be aired and considered by people in the group
If anonymous, perhaps more honest answers will be provided
Questions can be planned ahead of time by the analyst
Take up a lot of time for both individuals and the analyst
Must be well structured to be efficient - it is easy to waste time in an interview
Only practical for a limited number of people
Less quantitative than a questionnaire
People have to be available
Not as anonymous as a questionnaire so people may be less willing to convey the truth.
This involves a survey of current or potential users or a representative group of users who complete a set of questions in order for the analyst to find out the requirements and problems. The questions may be open or closed and are aimed at identifying detail on the current processes and data.
Can get answers from a lot of people in a relatively short space of time
They provide lots of data for analysis and the more data sets, the more accurate the analysis
Everyone answers the same questions i.e. same information is requested. Reduces bias.
Allows people to answer at a time convenient to them
If anonymous, perhaps more honest answers will be provided
Questions can be planned ahead of time by the analyst
The questions are set before and cannot be changed in light of a user's response.
Only as good as the questions being asked. If the questions are poorly worded or they are biased then the data obtained might not give an accurate picture.
Can be difficult for the analyst to ask the right questions if they are unfamiliar with the system
The response rate may be poor - especially if people are busy or don't see the benefit in answering
Difficult to allow people to expand on their answers, especially with closed questions
The analyst inspects existing documentation such as orders/invoices/reports to identify the current system’s inputs and outputs and the volume of data stored and how data is collected and stored
Excellent for tracking data flow
Excellent for identifying data types and formats
Useful to identify inefficient data flows so making the new system better
There may be other important data that are not actually in the documents
Cannot capture the efficiency of the process. Speed/delays etc
Does not help with understanding how people actually use the data
This involves the systems analyst shadowing users carrying out a particular everyday tasks. It allows the analyst to see at “first hand” what the user’s role entails and the data and processes required. It also allows the analyst can get a better idea of time required to do a task, constraints and strengths of the current system.
Useful if there are no documents involved the system
Can spot inefficiencies in the system and help identify persistent problems
Analyst can rapidly understand first-hand what the system needs to do
Users can impart their experience of the system directly and helps measure how long things take to complete.
People may feel intimidated being watched
People may be following the process to the letter (Act Up) rather than day-to-day practice
Take up a lot of time
Analyst may be in the way on a busy day
Not so efficient at capturing quantitative data for analysis
There may be 'good days' and 'bad days' with the system which one observation does not capture
Functional and Non-Functional User Requirements
The functional requirements of a system will specify the activities that a system must be able to perform or provide for users. Typical functional requirements will describe functions such as how data is to be entered into the system, descriptions of outputs such as queries and reports and descriptions of operations performed by each screen. While functional requirements describe what the system should do, non-functional requirements describe how the system works.
(Think of your GCSE Database CW - specific things like reports, forms etc. for Clients, Orders, Products. These are things the client need to do to help run their business. Think of the things that you would see on the Main Menu of a database.)
Non-functional requirements focus on specifying criteria that will judge the operation of a system as opposed to the activities to be carried out such the time (response time) it will take updating a stock database. Other non-functional requirements will include criteria for usability, security and access to the system, storage capacity, and maintainability. If we consider security and access to the system the non-functional requirements will specify frequency of backup of data, recovery procedures, contingency planning and access restrictions. Access restrictions will specify what data needs protected and what data should be restricted to a particular user role and level of access such as “read only”. All new computer systems are subject to legislation such as the Data Protection Act.
(Non-functional requirements - don't relate specifically to the operation of the system i.e. not the functions which would be on your main menu. )
A functional requirement
A process relating specifically to the application which must be provided [1]
UR103 - Automatic daily and weekly sales reports [1]
A non-functional requirement
An additional process, not relating specifically to the application, which must be provided [1]
UR101 or UR102 [1]
Data flow diagram (DFD) shows how data moves through a system and what data is stored.
It does not specify what type of data storage medium is used or how the data is stored.
The following table shows the symbols used when constructing a DFD.
Describe how a context level DFD is used to create a Level 1 DFD [4]
The context level DFD is refined to a level 1 DFD
The main processes are identified
The data stores are identified
The data flows are identified
... between the processes and the data stores
... between the external entities and the processes
CCEA 2024 Q2 D
When approaching this question identify the PROCESSES, ENTITIES (Data source), DATA STORE and DATA FLOW.
The application is logged, an acknowledgement sent to the employee and the Applicants file is updated.
The application is reviewed and accepted or rejected and the Enrolments file update.
Once you identify these, this will help you draw the diagram. You will pick up a lot of marks even if you don't get the diagram completely correct.
CCEA 2023 Q2A
When approaching this question identify the PROCESSES, ENTITIES (Data source), DATA STORE and DATA FLOW.
When a student applies for a course, the application is processed as follows:
The course file is checked to see if there is a place available on the course.
If no place is available, the student is sent a rejection letter.
If a place is available, the student is enrolled on the course and sent an acceptance letter, and the course file and student file updated.
CCEA 2022 Q3d
When approaching this question identify the PROCESSES, ENTITIES (Data source), DATA STORE and DATA FLOW.
Students provide the College with their personal details, their GCSE results and details of the course being applied for. The College validates each application. If the application is invalid, a rejection letter is sent out. If the application is valid, an acceptance letter is sent out and the applicant is registered as a student and enrolled on the course. Data about each registered student and the courses he or she is enrolled on is stored in a file called Student. Data about each course is stored in a file called Course.
As you can see in the mark scheme it is a simple diagram - in my opinion this should have included two more processes: registering the applicant and enrolling them on the course. It doesn't even include the Student entity.