Use of Appendices in a Technical Report

Dr. Faith A. Morrison
19 September 2015

Unlike a title, an introduction, a conclusion, etc., an appendix is not required in a report.  An appendix is a section at the end of a report that holds information that is not essential to the understanding of the report.  It may seem that information that is not essential should just be omitted from the report.  This is often the case.  There is some "non-esential" information, however, that may need to be available to some readers of a report.  Items to be included in an appendix include,

1. Raw data and final calculated numbers. Most readers of a report will not need your raw data or final calculated numbers, but the person who picks up your project after you leave it will be very interested in the raw data.  Also, you may wish to have an archive of your data, and including it in the appendix of a report is a good way of organizing such an archive.  In CM3215 lab, I want the raw and calculated numbers in the appendix so I can more readily check your numbers if they do not look right.  Put the numbers in scientific notation if necessary to reduce the number of digits shown to no more than 4.  There will be some "insignificant figures" there, but it's good to have that in intermediate numbers, and this is okay in an appendix.
   
2. Error propagation and error analysis.  Data are never completely certain, and we use error propagation and error analysis to put appropriate error limits on our data.  Errors can come from random events (accounted for with replicate error), reading error (from how an instrument reads) and calibration error (based on how the instrument is calibrated).  Calculated numbers have uncertainty associated with them through the process of error propagation.  The details of these calculations can be extensive, and including them in the report would often reduce the readability of the report.  Also the details of the error analysis may be of interest to only a small group of people.  For this reason, the details of error analysis are often left to the appendix.
   
3. Equipment instructions.  A report typically gives a general desciption of methods used and also detailed disscussions and interpretations of the results.  It is not necessary in a report to give step-by-step instructions on how to operate a particular piece of equipment.  Having such a step-by-step instructions would, however, be very useful for your own records in case you need to go back to that equipment, and it would be quite useful to the person who takes up the work after you.  It may be helpful to include such instructions in an appendix.
4. Derivations.  A technical report should be as short as possible.  In the service of this goal, detailed derivations are often not included in the body of the report.  In preparing the report you may have spent a great deal of effort in tracking down a particular derivation, however, and you may wish to be sure that you can find and comprehend the derivation some time in the future.  You can make sure that you (and your readers) have access to such derivations if you include them in the appendix.  If the derivation is easliy accessed in a published source, however, it is better to cite the derivation rather than repeat it.
5. Sample Calculations.  If you wish to record how you carry out tricky calculations, you may choose to put them in an appendix.
   

Important issues to note:
A) Nothing essential to the report goes in the appendix.  Since the appendix contains "non-essential" information, it can be stripped from the report when the document circulates, saving paper and shortening the report (always a good thing).  It is therefore very important to never place anything essential in an appendix.  Any data, tables, graphs, lists of nomenclature, names, addresses, etc. that are needed to justify or understand the content of the report should be contained in the report and not in an appendix.  If you are confused as to whether to include information in the report or in the appendix, imagine circulating the report without the appendix.  If it can be done, the information can go in the appendix; if it cannot be done, you must find a place for that information in the main body of the report.
B) Do not "call out" individual tables from the appendix.  Usually you refer to things in the appendix by saying "see the appendix."  If you find yourself needing to refer to "Table 3A in the appendix" perhaps the table in important enough to be put into the report.

Some details on writing appendices:

1. If there is only one appendix, call it the Appendix, not Appendix A.  Most reports have only one appendix.  Certainly nothing you write for your undergraduate degree will require multiple appendices.
2. If there are multiple appendices, call them the Appendices and designate them by letter or number (letter is more common, e.g. Appendix A, Appendix B, etc.).
3. Title your appendices following the style you would use for a figure or table caption.  For example, "Appendix A:  Raw data of pressure versus flow rate."