Spreadsheet design an overview of further issues Research Methods Group Wim Buysse – ICRAF-ILRI...
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Transcript of Spreadsheet design an overview of further issues Research Methods Group Wim Buysse – ICRAF-ILRI...
Spreadsheet design
an overview of further issues
Research Methods Group
Wim Buysse – ICRAF-ILRI Research Methods GroupOctober 2004
How to get the perfect spread sheet ?
Data entry: When ?
ASAP !(As Soon As Possible)
before you forget the details
Data entry: what ?
•RAW DATA• Do calculations and conversions
afterwards, in the spreadsheet using the computer– Formula in MS Excel– Also consistency check
9/11 or 11/9 ?
Outside the USA,
customize the regional settings !!
Do not leave ‘gaps’
Heading information
• Design factors, measurement variables => detailed information
•Column titles, codes
•Don’t leave blank
•Short
•Avoid using “strange” characters (%, $, @, …)
•Otherwise
• summaries / filtering
• importing in other software
Heading information
Heading information
Calculations ?
Calculations
- Use spreadsheet or statistical software
- Use figures
- Let computer do the calculations
- Use Forms to easily write down information when in the field
- Enter data on the computer in a way that they are easy to use in further calculations
Calculations
Same data entered in our standard format
Calculations
Now it is just a matter of presenting the data in the way that best fits the needs
CalculationsEven a participants list can be used to discover trends
One observation/answer per cell- How many training activities took place per location ?
- What was the total number of training days ?
One observation/answer per cell- Our standard format…
- (still data missing)
One observation/answer per cell- How many training activities took place per location ?
- What was the total number of training days ?
Confusing entries- What does 0 mean ?
- What does a blank cell mean ?
- What does an asterisk (*) mean ?
- What does 99 mean ?
AGAIN:
- DO NOT mix figures and text => calculations
- make sure the same code is written in the same way (N/A, n.a., not avail., ….)
- do not forget or mix meaning of codes, ex. 1 = male, 2 = female or vice versa ?? => should not be problem when using standard format
Confusing entries- Solutions
- documentation (description of design factors, description of measurement variables, experiment details)
- insert comment
- add column with comments
- if lots of comments
- easy to find (AutoFilter)
Include or exclude ??
- Include all cases ??
-The short answer is INCLUDE
- Analysis later can be done on subsets
- Insert comment if you think it is a strange observation
Include or exclude ??- Include all variables ??
-The short answer is INCLUDE
- Variables => depend on objectives
- Variables => do not forget to include important design factors like location
Include or exclude : example
Is there any significant difference between apple variety Anna and Golden Dorset in terms of flowering, fruiting and agronomy in the different orchards (= different altitudes) ?
Include or exclude : exampleExample = ‘nice try’
- Gives useful information
- Easy to collect data
(workers in orchards can do it)
- So, research is carried out at almost no cost
Include or exclude : example- Problem: which trees ?
- What happened with the apples (harvested, fallen, eaten by birds, … ?)
- (Probably) flowers and apples were only counted on those trees that were flowering.
- The problem is that this way we’re looking at groups of different size and with different variability.
- We can only answer a question like: of all those trees that are flowering at a given moment, where do they flower the most and where do they have most apples hanging on the trees?
- Solution = include ‘tree number’ as an extra factor + record what happened with the apples.
Unit or level of analysis• e.g. farm/household, person, plot, community,…• Is determined by objectives• Multiple objectives may require data at different levels• One row of data per case• If data are measured at several levels, move data between levels:
Unit or level of analysis• replicating data down levels
farm HH sex HH income1 M no2 F yes3 M yes.
Analysis at plot level
plot crop area farm hhsex1 m 0.1 1 M2 b 0.3 1 M3 b 0.2 1 M4 m 0.4 2 F5 m+b 0.2 2 F6 b 0.3 3 M.
Data at farm level
Unit or level of analysis• Summarising up levels
Data at plot level Analysis at farm level
farm HH sex mono beans bean area1 M y 0.52 F n 03 M y 0.3.
plot crop area farm1 m 0.1 12 b 0.3 13 b 0.2 14 m 0.4 25 m+b 0.2 26 b 0.3 3.
No unique way – think!