This guide is intended to answer any questions you might have about the Biostatistics consultation service.

BEFORE THE FIRST CONSULTATION

Make an appointment by contacting Marie-Pierre Sylvestre by email (marie-pierre.sylvestre.chum@ssss.gouv.qc.ca) or by phone – (514) 890-8000, ext: 15907.

Required services: When making an appointment, briefly indicate the required services (advice, analysis, protocol review, article writing or review, calculation of sample size, etc.), your availability and the timeline for your project. This initial contact serves, among other things, to determine whether the consultation service can help you and, if appropriate, to set a time for an appointment.

Rates and billing: This initial contact also serves to determine whether or not you are eligible for the rate for CRCHUM researchers, $35/hour. For all other clients, the rate is $70/hour. For more details, please consult the Rates and Billing section of our website.

What is billed?: Billable time includes consultation appointments, review of all necessary documents prior to the consultation, review of all relevant scientific literature, all requested analyses and writing, time devoted to all other contacts (telephone, email) related to the consultation, and all other requests for expertise. The initial contact to request a consultation is not billed.

Services are billed on a half-hourly basis, with a minimum of 30 minutes.

Once an appointment has been made, you will be asked to supply the number of your CRCHUM research account and your coordinates (email address, telephone number). Your account will be debited the amount corresponding to the invoice for services rendered. External clients or those who do not have a CRCHUM research account are required to pay for the services by cheque once the work has been completed or upon receipt of monthly invoices for longer projects.

CRCHUM students, postdoctoral fellows and research personnel must ask the researcher responsible for the research account to be billed to send an email to the biostatistics consultation service authorizing the consultation and supplying the research account number.

Timeline: During the initial contact, please indicate when you would like to see the work completed. Since the demand for consultations is quite high, 10 working days are generally required before work can begin on your project.

Please note that priority is given to CRCHUM researchers, investigators, students, postdoctoral fellows and research personnel.

INITIAL CONSULTATION

Consultation appointments generally take place at our offices, located at 3875 Saint Urbain, suite 308. In certain cases, the consultation may take place by telephone.

The initial appointment generally lasts around 30 minutes.

PREPARING FOR THE FIRST APPOINTMENT

Documents to be sent: You do not have to send your data before the appointment. However, if you wish to reproduce an analysis discussed in a journal article, please send it before the appointment. When appropriate, you may also send a protocol or an article to be reviewed. Please note that all work of this nature done prior to the appointment is billable.

Clarification of research questions: For all data analyses or for validation of the analytic methods you wish to use, please clearly explain your research questions, taking care to indicate which questions are primary and which are secondary. Since the members of the biostatistics consultation service are not physicians or biologists, you will probably be asked for a brief explanation of a few concepts relevant to your project.

Although (bio)statistics are widely used in biology and medicine, the jargon used can vary considerably from one field to another. Therefore, do not be surprised if the consultant requires some time to review the relevant scientific literature and determine which method is the most appropriate for your data. Please note that all reviews of this nature are billable.

Database: If you request an analysis of your data, you must supply the database at the first appointment.

It will likely be necessary to view the data during the initial consultation. The consultation service has software to view Excel, R and SAS files. If you are using another file format, such as SPSS or Stata, you should export your data to an Excel file or to CSV or print an exhaustive list of the variables included in your database and bring it with you.

Some tips: All analyses begin with a descriptive analysis of the data, in which the distribution of variables, missing data and aberrant values are examined.

To limit the time required (and billable hours!), please follow the following instructions:

• For Excel files, do not include macros or links between worksheets;
•  Use short names for variables, without spaces, without accents and without any of the following characters: + - . ! < > = _
•  Do not use colours to identify a category of subjects; use a categorical variable instead;
• When a datum is missing, leave the cell empty (do not write NA or X or .).

N.B. – To preserve confidentiality, do not forget to remove identifying details from your data

Data structure: if data are to be discussed (whether for a complete analysis or for general advice), it is essential to explain their structure.

You will be asked to explain:

• The design (cohort, case control, etc.)
• Subject selection
• The chronology of the measured variables (e.g., patients with a trauma X are subsequently measured once for factor Y; they then receive treatment Z and are once again measured for Y).
• In the case of multivariate models, indicate the variables to be considered according to your knowledge of the relevant literature.

Calculating sample size: In the vast majority of cases, the required sample size is determined on the basis of the study’s main hypothesis. This hypothesis and the study design will determine a comparison (test or model), according to which the required sample size will be calculated. Therefore, you must be able to clearly articulate both your hypothesis and the comparison that will be used to test it.

ESTIMATE OF HOURS

Before the end of your first appointment, the consultant will provide you with an estimate of the number of hours required to complete the requested work. This estimate is an approximation based on the best of our knowledge and may vary upwards or downwards, particularly in the case of complex projects or in the event of unforeseen complications. You will be notified accordingly.

FOLLOWING THE FIRST APPOINTMENT

You will receive a written report once the work has been completed. Further questions, comments or requests will be discussed by telephone, email or, when necessary, by appointment.

Please let us know about protocols accepted or articles published after you have used this service.


Questions? Comments? Suggestions?

Please contact Marie-Pierre Sylvestre by email (marie-pierre.sylvestre.chum@ssss.gouv.qc.ca) or by phone – (514) 890-8000, ext: 15907.