It may increase the quality and the quantity of the resulting output. However, option symbolgen in pharmaceutical research all generated SAS code has to be validated, including newly developed macros. Though the validation process may be partially the same for dedicated SAS option symbolgen and macro code there are also obvious differences between them.
SAS macro option symbolgen involves many issues, which can mainly be option symbolgen into the following categories: The various characteristics of standard SAS macros will be discussed option symbolgen their implications regarding validation.
SAS macros, performing general routine tasks, which are being written with the purpose to be widely useful in various areas of research, or in certain specific areas, like pharmaceutics, can be called standard or general macros.
Once written they serve to save the user a lot of work and time, they limit the chances on programming errors and they promote standardization of output, whether that consists of datasets or tables, graphs and the like. But, as with many other new solutions they have to prove option symbolgen, they have to be tested, it has to be verified that they do what they pretend to do, nothing more, nothing less, always, without errors, reliably and justified.
They have to be validated and approved, certified. And once approved they have to be validated again after every change, bug fix, new feature and so on, at least for the part that has changed but rather option symbolgen again and preferably in the environment calling programs where they are being option symbolgen. Macros automate and replace often applied and written as dedicated source code functionality option symbolgen SAS programs in a very easy and generally applicable way.
Macros may be run from the original source code as well as in a compiled, unreadable form. From a user point of view a standard macro may be regarded to be divided into two logically different parts:. Developer The option symbolgen programmer option symbolgen has to do with the macro source code and the comments therein.
The advantages of developing, maintaining and validating SAS macros are: The main purpose of the validation process is to check whether the program, a SAS macro in this option symbolgen, serves its main goals, which generally are:. Input to a SAS macro is considered to consist of both data e. Outlined in brief SAS macro validation should consist of the following aspects more or less in chrono logical order: Testing with known, provided data and known results, check for correct results white box testing 2.
Testing with option symbolgen data and unknown results, check for plausible results black box testing 3. Testing with all variations of argument option symbolgen parameters, check their effects, testing with existing but known erroneous data and argument parameters fool proof testingcheck for appropriate responses, error reports and their consistent layout and verify whether all parameters are being checked on validity legal SAS names, limited options, numbers, etc.
Verify logic of default values of parameters of arguments, if any 5. Read source code, verify correct programming according to functional specifications and the extent of algorithm efficiency 6. Check for descriptive heading and user documentation with examples, purpose and verify presence of identifying information: Verify the presence of a version numbering system and preferably version control support 8.
Verify presence of history of development, each change briefly indicated and especially check changes from last version see historyall option symbolgen of bug fixes 9. Verify readability, layout of source code and substantial amount of comment, and check for grammatical errors and typing errors, especially in comments Verify that all macro created temporary SAS variables in temporary datasets have unique names stored as macro values Verify that all macro created temporary datasets have unique names stored as macro valuesnot interfering with others and verify that they explicitly are deleted after use also option symbolgen case of errors Check for sufficient flexibility, allowing the user to specify titles and footnotes outside the macro instead of fixed macro generated title and footnotes Verify readability, layout of readable output tables, any resultspossibly standard footnotes on each output page with date, SAS version, macro name, version.
Check log files for easy reading macro log part, incl. Verify optional debugging system options for feedback in log file Verify presence option symbolgen auxiliary macros separate or appended in same file Verify presence of a option symbolgen plan or procedure for SAS option symbolgen macro code validation or write it Write validation report, both in case of approval and disapproval Optionally sign the validated macro electronically e.
These aspects of macro programming and option symbolgen will be discussed in detail below, not only from the option symbolgen of the person who does the validation, but also from the viewpoint option symbolgen the developer, who may account for the validation process and improve his macro accordingly.
Next to a large amount of advice on many aspects of macro validation many programming hints are issued with respect to improving macro code quality. Such quality may reduce validation option symbolgen, increase chances on a positive outcome of the validation process and last but not least increase user-friendliness. Testing with known, provided data and known results, check option symbolgen correct results white box testing.
First of all a macro should be tested in the context it option symbolgen meant for. Appropriate, legal parameters should be specified for its option symbolgen, preferably default parameter values.
Valid and appropriate, existing datasets option symbolgen be used of which the contents are option symbolgen. It should be clear what the result of the macro processing should be option symbolgen terms of output datasets or output listings. These should be verified for correctness and possibly checked against other known correct option symbolgen. This is the main kind of testing that a developer carries out too while developing his macros.
These tests of course should be completely successful; that is the goal of the macro. Black box testing should carried out by trying all input options one at a time, while all the time normal output should be produced.
This does not necessarily include all possible combinations of input options under all possible circumstances. It may be virtually impossible to check all possible variations in the functionality of a complex macro. During development new features have been option symbolgen one by one and tested in their target environment mainly, while testing them in other option symbolgen might be either redundant or option symbolgen applicable.
So is validation, though during the validation process it may be difficult option symbolgen judge sufficiently reliably in which situations additional checking is superfluous. Thus during validation checking actually should be performed at least as option symbolgen even more extensively than option symbolgen development. This is one of the most important tasks of the macro: It should know that datasets, that are to be processed read, analyzed and hence expected to exist, do indeed exist.
If such a dataset does not exist, the macro may as well abort. This also applies to user specified variables as macro parameters. A newly to create dataset on the other hand actually should not yet exist or should be allowed to be overwritten. Furthermore legal names have to be user specified, illegal names of course do not exist either but can not be checked with respect to that and neither can be created.
Cross checks are necessary to determine the possible presence of legal, but option symbolgen parameters e. Finally a macro may have a limited number of specific arguments numbers, letters or words. A macro should extensively check all parameter values and during the validation process not only the option symbolgen code has to be studied to see whether these checks are present, but the macro should also extensively be checked whether it can get to a state that the macro author did not foresee and which aborts the macro in a very user unfriendly way, generating many SAS errors, or a state in which the macro continues producing erroneous results.
If it has been programmed fool proof it should react to any inconsistency in a user friendly way with a clear error message and abort without producing any results if possible.
A brief example is option symbolgen small part of the parameter checking within a macro:. Option symbolgen difference between white box, black box and fool proof testing is that white box testing consists of checking a few known situations, similar to the situation s which led to the development of the macro.
User specified parameters are only legal and correct. Black box testing also tries to check legal, comparable, complex, but yet unknown situations to see whether the macro is suited for those too, while fool proof testing tries to crash the macro, while it never should.
Macro parameter values may have default values, which should be quite appropriate in most cases. The default input dataset, for instance, might be set to the last dataset processed in the SAS program at that point, just like the default for quite some PROCs. Other default values may indicate the most common statistics to be calculated valid number, missing number, mean, standard deviation, median, etc. If the macro option symbolgen a new permanent dataset, named by the user, then that name should be assigned to option symbolgen variable SYSLAST in case of successful processing.
Other default values are very much macro dependent. It is left to the judgment of the validating person to decide whether choosen default values are appropriate in the context. Here the validating person should focus on the SAS code, the algorithms applied and their efficient programming.
He should try to understand the program code and to judge not only whether the solution was programmed efficiently and optimally, but also whether it was programmed correctly at all.
In order to option symbolgen a reviewer to interpret the program code as good option symbolgen possible it is very much necessary to keep the code short and logical, not more complex than needed, option symbolgen neither more compressed than needed. Furthermore the need for extensive comments within the program code can not be sufficiently stressed. These facilitate the validating person, as well as another programmer, taking over the option symbolgen development, to quickly understand the code.
Keyword parameters should preferably be used in the macro argument list, to avoid user errors while calling the macro. Only if a macro has only one parameter, option symbolgen positional parameter is appropriate. Macro program headers may take many forms. The main objective is readability and amount of information about the macro and its arguments. If there is no separate documentation, like a Word document, the documentation should be option symbolgen of the header comment.
That is the most important aspect that has to option symbolgen verified. A proposed layout is:. The main question is: This is option symbolgen be judged by the validating person.
Next to their descriptive names macros should preferably have version numbers to discriminate various stages in the development of them and to be able to check whether one has the last version. The last maintenance date should, in the macro comment, be related to the version number. The number should preferably not be part of the name.
It may vary from a very simple, single sequence number to a complex numbering scheme as often present with commercial or important software. Option symbolgen suggestion is a multi-part number, consisting of a major number part, a minor number part, and patch or revision or maintenance part.
Possibly a build part can be added, which is for internal use option symbolgen during development. An example of a Major. Build] number is 2. All numbers start at option symbolgen and a validated first release should have number 1.
Validated versions may have even minor numbers, experimental, but not yet validated versions may have odd minor numbers. During the development and maintenance life-cycle process of SAS macros, especially while they are already used for production purposes, it is very much recommended to keep a history of changes, additions and bug fixes along with the macro version number.
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