As student information, assessment and examinations officer at the 1,200-pupil Ernulf community school in St Neots, Cambridgeshire, she spends most of the year processing entries and preparing for the exams season.
The run-up to the main six-week season is busy enough for Ms Jarvis. The autumn term embraces re-sits, analysis of the previous year's results and overseeing students' grading appeals.
This term, teachers must complete forms to show the subjects pupils are to be entered for and the modules within that subject. They must also predict grades in each subject.
These details come to Ms Jarvis on paper. She enters them on to a computer and sends them to the board. She must notify the board if pupils are dyslexic or need special provision in exams. She then has to collect and send coursework marks for all of the pupils - Ernulf has about 220 taking GCSEs and 180 doing conventional and vocational A-levels - and samples of student coursework to the boards.
Before the exams, she must organise seating plans, co-ordinate invigilators, prepare the examination hall and draw up individual student timetables. Throughout the year, this work takes up much of Ms Jarvis's 30-hour week, none of which is spent teaching.
During exams Ms Jarvis says it would be especially tough to teach as well.
She says it is good practice for an exam officer to start each exam and that she should be there at the end to collect the papers as she is reponsible for them reaching the board. Any unforeseen problems, such as students receiving the wrong paper for an exam, would mean alerting the officer at once.
She says: "I am in my office, I am contactable at all times - but if you are teaching it would be more complicated to deal with the problem. You would have to get someone to cover your class.
"I cannot understand how a teacher could possibly do whatI do."