Instruction about methodology please follows it: 1-intoducation about what the meaning of methodology in general in nursing research with updated references 2- Research objectives in my study 3- Research design (introduction about what the meaning of design in nursing research with updated references) and write also (introduction of retrospective and case control study and reference with updated references ) 4-setting introduction in nursing research with updated references and write about my study (King Abdul-Aziz university hospital) medical record department by using patients files and electronic files . 5- Sample( introduction about sampling from nursing research with updated references ) And write about my sample ( size , type, duration ): it was 120 data base in (medical records) during :2011-2013 start collecting from ( 15 October 2014 ) to ( 15 December 2014 ) and inclusion and exclusion criteria ( please check my proposal) 6-data collection tool (check list modified by me) In details: modified to be more specific about the risk factors of CABG ..it was general chick list it is( bundle of surgical site infection)>>> please write this by scientific way of writing and write more reasons 7- Check list include ( you have check to chick list form) it is filled by me form each patients file ( 1- demographic date (2- Patients factors (3- Preoperative factors (4- Introperative factors (5- Postoperative factors (6- Wound infections (7- Nursing management 8- Producer first write introduction about ethical approval ( from nursing research study ) with updated references (1- ethical approval it is approved from ( i have to check the ethical to see the name of place and date and time that start to collect ) date ( ) : i gave to director of medical record department and he is agree to come 3 days per week from 12- 14 pm (2- Consent form: it was not because the director agree with ethical approval (3- Validity : please write here more details from nursing research (4- Pilot study (here I did not do pilot study because it is retrospective so here write this with evidence and references it is very important.9- Data collection: collected in king abdulaziz university hospital (from medical reports) How long: 120 cases in 2 months (please clarify type of data and number and how long time collected) i went there 3 days per week from 12-14 i was there ..i was checking the patients file and electronic files in phoenix system and i filed all data by spss sheet 10- 3 cases are missing (please write here about this (because some data about this are missed and not clear. 11- Summary And please follow this twelve steps also when you are writing Twelve Steps to Writing Effective Materials and Methods1- You must describe exactly what you did: what and how experiments were run, what, how much, how often, where, when, and why equipment and materials were used. The main consideration is to ensure that enough detail is provided to verify your findings and to enable the replication of the study.2- You should maintain a balance between brevity (you cannot describe every technical issue) and completeness (you need to give adequate detail so that readers know what happened).3- Since each journal has different requirements, review the journals guidelines before beginning to write this section. The steps listed here are a general compilation of these requirements4-Order your procedures chronologically or by type of procedure and then chronologically within type of procedure using sub-headings, where appropriate, to clarify what you did. It is up to you to decide what order of presentation will make the most sense to your reader.5- Use the past tense and the third person to describe what you did. For example: The sample was incubated at 37C for 3 days. NOT: I incubate the sample at 37C for 3 days.6- Describe your experimental design clearly, including the hypotheses you tested, variables measured, how many replicates you had, controls, treatments, etc.7- Explain why each procedure was done. Reference may be made to a published paper as an alternative to describing a lengthy procedure.8- Identify the source of any specific type of equipment, a specific enzyme, organism, or a culture from a particular supplier, which is critical to the success of the experiment.9- Describe in detail any modifications to equipment or equipment constructed specifically for the study and, if pertinent, provide illustrations of the modifications.10- Precisely quantify measurements (all metric) and include errors of measurement.11- Describe the dates and the site where your field study was conducted including physical and biological characteristics of the site, if pertinent to the studys objectives.12- Identify treatments using the variable or treatment name, rather than an ambiguous, generic name or number (e.g., use healthy donors rather than group 1).13- If required by the journal, mention the approval for the study by the relevant ethics committee(s) and the informed consent of the subjects.14- Describe statistical tests and the comparisons made; ordinary statistical methods should be used without comment; advanced or unusual methods may require a literature citation.15- Show your Materials and Methods section to a colleague and ask whether they would have difficulty in repeating your study.16- Other points to consider when writing the Materials and Methods:1- Dont mix results with procedures.2- Omit all explanatory information and background save it for the discussion.3- Dont include information that is irrelevant to the reader, such as what color ice bucket you used, or which individual logged in the data.