I'll take exception to Brent's response. If the candidate misses all the questions on the subject of WPSs and PQRs the individual is definately going to fail the SCWI examination. The SCWI exam is heavily weighted toward that subject. The other subjects emphasized are NDE and QC/QA.
AWS B5.1 Table 1 outlines those subject areas and job responsibilities the CAWI, CWI, and SCWI are expected to fulfill. The examinations are developed to "test" the candidate's mastery of the subjects the inspector is expected to know. The number of examination questions on each subject are specified and provides an indication of the weight given to each subject area. However, in the case of the SCWI exams the subjects overlap and to a large extent apply to the major categories I mentioned, i.e., procedure qualification, developing the WPS, NDT, and QC/QA. The candidate may be "weak" in one question category, but failing all the questions relating to a question category or a weakness in several question category is a sure way of failing the examinations.
Back to your question; there are few questions on the CWI examination relating to the WPS. The new practical examination requires the candidate to use a WPS and supporting PQR to answer specific question relating to the ranges appropriate for the WPS based on the PQR. There are several questions relating to the interpretation of test results, i.e., was the UTS properly calculated, etc. However using a WPS is not the same as developing a WPS. The CWI isn't expected or required to know how to develop or write a WPS. Few new CWIs are prepared to develop a WPS and the CWI examination does not include question that would assess the candidate's ability to do so. The SCWI is expected to know how to write and qualify a WPS and the SCWI examinations do assess the individual's ability to develop a basic WPS.
That being said, the B5.1 does not prohibit the CWI from developing a WPS if he or she has sufficient back ground and experience. Many CWIs develop those skills over time. It is beneficial for a new CWI to team up with a more experienced CWI or welding engineer that has experience developing WPS. The CWI can also learn how to develop a WPS by taking classes that are related to subjects associated with developing WPSs. For instance, courses in material science, manufacturing, metallurgy, mechanical testing, etc. provide useful back ground that can aid someone that has to develop a WPS.
Writing a WPS involves more than "filling in the blanks". While writing a prequalified WPS appears to be an exercise in doing just that, but it can become much more involved when joining dissimilar metals, high performance steels, etc.
I hate turn this into an advertisement, but here goes; I am offering another three day seminar on the subject of welding procedures, documenting the qualification effort, i.e., the PQR, and welder qualification in October 2018. The seminar was offered this past March and it sold out very quickly. The feedback was very positive, so I am offering it again. The seminar can be offered by local AWS Sections or Districts as an educational seminar and as a means of raising funds for their local section. An AWS section in western US is currently in the planning stage of offering the seminar, titled The Atlas of Welding Procedure Specifications, in early 2019 as an educational seminar. The point being, there are venues available to obtain the knowledge needed to develop WPSs that go well beyond what is covered by CWI seminars or the CWI examinations.
Best regards - Al