Unit H3 - Recording and Analysing Data


Unit H3


No one can keep everything they have seen in their head. We all have a tendency to forget things as time passes. If someone moves away or dies, their knowledge and experience are lost to the community. Therefore all societies have developed ways of making and preserving records, ranging from oral traditions passed down from generation to generation, through scratchings on stone and clay, to written records and computer databases.

One of the most essential parts of any scientific work is the careful recording of the results or observations, and the same is true for any description or monitoring of the local environment. Making careful records will take some time, but it is not necessarily difficult, and for some kinds of data it is not even necessary to be able to write well. What is important is that you (or even someone else) can go back to your records several years later and understand what happened or make comparisons.

What to record

The first step in making a record is to know what to record. Three types of information are essential for any record:

This is the content of the record. It could be the amount of rainfall in a day, the lengths of each fish caught, the description of a diseased banana leaf, a map of the area flooded in a cyclone, or the data on a monitoring circle in a forest. Whatever it is, it should be described as completely as possible, so that there can be no doubt as to exactly what is meant. Do not forget to show how the measurement was made and what the units of measure are. If some of this is the same for every record, it can be included once at the beginning in a description of the methods used, and need not be repeated for each record unless there is a change in the method.

The place where the information was collected or the record was made should be clearly stated with as much detail as possible, so that someone later can go back and find exactly the same place.

Every record must have the day, month and year, and perhaps even the time of day, as these will be important in making comparisons with other months or other years, or to see if there is any change over time.

A record that is not clearly described, or that lacks the place or date, quickly becomes worthless, and the effort that went into making it is wasted.

Two other kinds of information are also very useful in a record even if they are not essential:

The person who makes an observation or record should include his or her name somewhere with the record. While you may know what you have done, it may help anyone else referring to the record later to know who made it.

There may be some special reason why you made the record or experiment, or some unusual event associated with the record, and this should be mentioned. Perhaps you are measuring fish lengths because you suspect an effect of overfishing, or the rainfall was very heavy because of the passage of cyclone Camille, or on the day of the bird count it was very hot and there was no wind. Such information can be very helpful later in interpreting the results. In the same way it can be important to know that there was nothing unusual or abnormal at the time of a measurement.

If there is any doubt as to the importance or usefulness of some information, it is always better to include too much and not use some of it, than to record too little and later find that you are missing something essential.

When making a record, always ask yourself if you have answered the five basic questions: What? Where? When? Who? Why?

How to record it

There are many ways to keep records. It all depends on what you have available and how the records are going to be stored and used. Most scientists keep written records on paper, but this may not always be possible or even desirable in a rural village. Some of the many kinds of materials for records are described below to show what is possible depending on local circumstances.

Paper is easy to write on and widely available, so it is generally preferred for written records. However, it can be damaged or destroyed if it gets wet, and, in the tropics, paper may turn mouldy or be eaten by cockroaches, silverfish, termites or other insects. Some cheap paper like newspaper also turns yellow with age and breaks into pieces. For records to be kept a long time, try to choose the best quality paper available.

Since individual sheets of paper can easily be lost or mixed up, it may be better to keep your records in a notebook or school exercise book. Then you know that the records will stay in the order in which they were made. If the records will be handled a lot, a record book with a strong binding or some other kind of protective cover may be desirable. Where records may need to be grouped later in other than chronological order, it may be useful to keep them in a loose-leaf binder or some kind of folder.

The kind of writing also can be important in permanent records. Most typewriters make good records, but they are seldom available in village areas. Ball-point pens or pen and ink are also good, but try to choose a permanent ink that does not wash in water, in case the paper accidentally gets wet. To test your ink, try wetting and rubbing a little piece of paper with some writing on it. Pencil can be erased or smudged if it is rubbed, but it is better than a washable ink if water may be a problem.

Computers are becoming more common even in rural areas of developing countries, so storing records in a computer is another possible alternative. However computers do not last forever, their components may fail or they may be stolen. Software and hardware change, so that records a few years old may not be readable in new machines. Computer records stored on diskettes, CD-ROMS, or flash memories may need to be moved to new storage media as the old technologies go out of date. It is always better to save copies of all data and records in different formats and in different places for safekeeping, especially in rural areas where the risks are greater. Keeping printed copies of all computer records is good insurance against complete loss of data.

Words and numbers are not the only things that can be recorded. Photographs, drawings, maps, pictograms (simple pictures), symbols, tallies or marks can all be used to record information. However, whenever possible an explanation of any symbols or marks should be included somewhere in the records so that others can understand what is written.

If paper is not available or not certain to last under local conditions, then records can be made on other things found on or around the village. Pieces of wood can be written on with ink or carved in with a knife. Writing or drawings can be scratched on bamboo and then rubbed with charcoal to make them more visible. Pandanus or coconut leaves, or cloth made from vegetable fibers can be used as a substitute for paper.

Other materials can also be used to keep some kinds of records. Lengths can be recorded with pieces of rope or string, perhaps with knots in them to tell them apart, or bundled by period of measurement. Counts or tallies can be kept on notched sticks or knotted strings. Cloth or oilcloth can be written on, and maps, rainfall measurements and other data can be stitched with coloured thread into pieces of cloth. Sheets of metal can also be used to write records on; aluminium beverage cans can be cut open and their sides flattened out to make sheets on which it is possible to write with a pointed instrument. Information can be embossed into clay like that used to make pottery, which can then be baked like pots to make permanent records.

What is perhaps most important is that the records, whatever they are written on, are kept in a safe place and protected from whatever might damage or destroy them. In rural areas, the greatest dangers to records probably come from water damage during leaks, floods or cyclones, insect attack, mould and rot, children damaging or losing records, and people accidentally misusing the material such as by taking the paper for use in personal hygiene. Much time, effort and irreplaceable information can be lost if care is not taken to protect essential records from harm.

Recording and documenting information

When recording an observation, try to include as much information as possible. For some things a sample or example of the object can also be preserved and kept for future reference. For instance, suppose you catch a new kind of fish. In the record, you would describe its size, colour, shape, where it was caught and by what method, etc. If you hope to have a scientist identify it later, perhaps the fish itself can be salted and preserved, kept in a sealed bottle with alcohol, or at least its skeleton could be cleaned and dried to show the scientist along with the description. Pieces of plants can similarly be flattened between pieces of newspaper or matting and dried to show what plant is referred to in the record.

There is a similar need to document any place referred to in a record, whether it be the site of an observation or the location of a marker. The place should be located on a map, or positioned by reference to some obvious and permanent features. This is especially important if you plan to go back to the same place later to repeat a monitoring survey. One way to describe a location precisely is to determine two lines of sight with pairs of obvious features; lining up the first two gives a line that one can walk (or swim) along until the other two features are also lined up to show where the spot is. These lines of sight should be described in the record, and perhaps shown on a sketch map as well. In choosing reference features, remember that trees can be cut or blow down, telephone poles can be changed, buildings can be torn down or replaced, roads can be realigned, and other features may not be as permanent as they seem. The longer you expect to wait between surveys, the more permanent the features should be. If possible, plan so that the loss of any one feature will not make it impossible to find the site.

It will often be necessary to make marks at the place itself to identify a site or survey area. Marks should be as permanent as possible, but not so obvious that they invite vandalism or disfigure the area. Anything of value used as a marker is apt to be picked up and taken away by someone. Important survey markers can be cemented into place. Identifying marks can also be chiseled into stone or cement, or cut into tree bark. Large nails can be driven into trees or coral (but remember that trees and coral grow and will cover up the marks if they are not renewed from time to time). Pieces of steel reinforcing rod can be driven into the ground, or into the reef, perhaps to mark the centre of a survey circle; short pieces of rod usually do not have enough value to attract attention, but they are not too difficult to find again, even in the middle of a coral reef.

When recording such things as the height of flood waters or the level of the sea, try to find a point of reference that is as permanent as possible, such as a ledge in the cliff, the wall of a church, or a large healthy tree. The next flood might not be for 30 years or more, and it would be valuable to have the same point of reference for comparative purposes.

Photographs can be very helpful to record the appearance or position of things if you have access to a camera. For a picture to be useful, however, you should record the same information for the picture as for any other record: what, when and where it was taken, and perhaps the exact position of the camera if you hope to take a picture from the same place later and compare the two.

Recording information underwater is a special problem. While waterproof paper exists that can be written on underwater, it is not generally available in most developing countries. However, a pencil can be used to write underwater on any surface that is a little rough, such as hard plastic or aluminium that has been rubbed with sandpaper, pumice or sand. The information written on such a slate can be recopied afterwards onto a notebook page or record sheet, and the slate scoured again to erase it for reuse. It is wise to tie the pencil to the slate with a string, as a wooden pencil can too easily float away.

Analysing data

The information collected in records such as those described above is usually not in the best form for easy analysis and interpretation. While some similarities or differences may be obvious from reading the records, there are often ways that the data can be converted to make them easier to understand. In a bar graph, for instance, the amounts in each record are shown as the heights of bars, usually in chronological order, like the rainfall bar graph described in unit H2. If several years are being compared, the data might be grouped by month, using different colours or shading for the bars showing each year's records.

Changes in land uses that have been mapped, or in monitoring circles that have been drawn, can be shown by overlaying the maps or drawings for the different records, assuming that they are all drawn to the same scale. The maps can be drawn on tracing paper, so that one can be seen through the other. If tracing paper is not available, redraw the maps on any relatively thin paper, and then lightly oil or wax the paper to make it translucent. By laying one map on top of the other, any differences between them can be seen very easily.

It can be interesting to compare the data from different places to see just how they are different, or to see if certain areas are sufficiently similar that they can be developed or managed in the same way.

Very often data from different years is compared to see what changes may be taking place over time, or to identify patterns or events that may repeat themselves at certain intervals. The data for each year then need to be organized so that the comparison between years can be made more easily. The same thing is done to identify seasonal changes. The data for each month or season are grouped and compared to show whatever differences there may be between seasons.

When you have collected a series of numbers, whether of the amount of rain, the fish catch, or the water temperature, there are some simple calculations that can be used to give figures that are easier to compare. For instance, it might be interesting to add up the numbers for each month to give a monthly total, or for the whole year to give the annual rainfall or total catch. If the total is divided by the number of months or the number of days, the resulting figure will be the average monthly or daily amount. Comparing averages can be easier than comparing all the data, since averaging evens out the small often random changes from one day to another. Since it is sometimes the extreme conditions that are the most important for the environment, it can be useful to determine the highest and lowest figures for each month, or for the whole year.

Even with these calculations, there is still the same problem of deciding if a difference is significant or not. The question of significance has already been discussed in the previous units. In general, the larger the number of measurements being compared, the greater the chance that the observed difference is significant.

Measuring effort

One type of analysis that can be very useful in studying the use of environmental resources is to estimate the effort that went into producing a certain result. For example, suppose 10 fishermen go fishing on 50 days of the year and catch 500 fish. The next year there are 12 fishermen each fishing for 50 days, but they still only catch 500 fish. The third year, the 12 fishermen must go fishing for 70 days each to catch the same 500 fish. If you looked only at the number of fish caught (500 each year), you might say that the fishing was just as good, but if you calculate the number of fish caught per fisherman per day spent fishing (in other words the fishing effort), the catch has become steadily worse.

It is thus useful to collect some records of the amount of effort (in area planted, hours worked, trees harvested, etc.) and include it in the analysis on order to see if any difference observed is the result of a change in the productivity of the resource or of the effort put into exploiting it.

Instructions for trainers in the use of this unit

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Last updated 22 June 2008