Using SIMIO software: Loan Application Process

Management of a large commercial bank has raised concerns about the process currently being used to handle loan applications. Commercial loans represent a substantial revenue source for the bank.

Applications for loans are first taken by the loan officer and then sent to the main office at an average rate of $4$ loans per $8-$hour day. A clerk at the main office checks the application for completeness. The time it takes for this initial check is uniformly distributed between $0\mathrm{.}5$ and $1\mathrm{.}0$ hours. Records show that $60\%$ of the applications checked are complete and these are sent to the loan processing department. $30\%$ checked for completeness are found missing one or more items and are sent back to the originating party for correction and re$-$submittal. $10\%$ are immediately denied. The time it takes for a loan application to be re$-$submitted is uniformly distributed between $8$ and $16$ working hours. Transmittal of complete applications to the loan processing department is carried out by an interoffice mail system and it takes $4$hours, $75\%$ of the time and $8$ hours the remaining $25\%$ of the time.

At the loan processing department, an application is assigned to $1$ of $3$ loan specialists who carefully reviews the application and makes a $$go$/$no$-$go$$ decision. The time it takes for these evaluations is uncertain but can be represented by a triangular distribution with a min of $5$ hours, a most likely time of $7$ hours and a maximum time of $10$ hours. Currently the loan processing department has $3$ loan specialists on duty. Over time, $80\%$ of loan requests are approved while $20\%$ are denied.

We want to:

$1-$ Model the above system

$2-$ Calculate the minimum number of loan specialists the bank would need to in order to get the average time an application was in the system to be less than $18$ hours?

$3-$ At this staffing level, what is the average monthly throughput of approved loans?

TIP: Use a transfer node to model the interoffice mail system. A transfer node is often used to model intersection points.