Most of us are familiar with Financial Debt. Let’s try to
draw analogy for Technical Debt from Financial Debt.
Short-term Debt
In financial domain, short-term debt is used to finance
temporary cash flow like financing of raw material for an order. As name
suggest, it is expected that short term debt will be paid back on priority,
generally short-term debt is expensive.
In technical domain equivalent short-term debt is debt
assumed to ship code to meet deadline with known bugs, having understanding
that immediately patch will released to fix the bug. Second example is hot fix
for a P1 issue. In all of cases, focus
is – let’s ship/fix the code NOW, resolve the issues in immediate future.
Long-term Debt
In financial domain, long-term debt is used to finance long
term goals of enterprise, generally investments like acquiring plant and
machinery, acquiring competitor, etc. Generally long-term debt is cheaper to
service. Long-term debts are assumed for strategic reasons.
In technical domain equivalent debt is writing a code which
is UNIX specific as most of the prospects are on UNIX. It is possible that
long-term debt is camouflaged as strategic architectural/design decision. When
long-term debt is camouflaged as strategic architectural/design decision, never
paid but does not mean it is free. There might be some opportunity cost
associated with it as never approached market segment.
Interest Payment
There is no free lunch. Once you assume debt, you need to
pay back it with premium. As a business and/or technical person, you need to
decide, can you afford the interest and absolute amount of outgoing benefits.
Technical debt can be pay backed regularly (with each
sprint), in spurts (with each release), in one shot (bug fix release). You may
also decide not to pay debt at all in case of end of life products.
Expected Cost/Value
If you purchase a car now, you may commute farther for job,
so potentially earn $2,000 extra each month. The car price is $10,000. If you
delay purchase of car, you may not have promised job. Are you willing to assume
debt to purchase car?
If you do not release product now (before FIFA cup), no one
will buy it. Are you willing to cut corners to meet the deadlines?
Opportunity Cost
What else can be done with this money/resources? Instead of
following the strict coding guidelines, can I cut corners and release the
product early and utilize saved (?) resources to release new features?
Present Value
Your startup needs this particular sale now even with lower
margin. Present value of debt is
function of Expected value and \opportunity cost.
Debt Service Coverage
Ratio
Debt service coverage ratio (DSCR) is the ratio of cash
available for debt servicing to interest, principal and lease payments.
In Technical debt realm, DSCR may be defined as ration of
resources available to develop software to resources spent to service technical
debt.
Credit Rating
Credit rating of any individual or business depicts
confidence of market in paying back the debt.
In software development domain, credit rating of a team or
product symbolizes the capacity of accruing/acquiring new technical debt. Team/Product having less technical debt and
specifically less unintentional technical debt has capacity to acquire more
technical debt.
Acquired debt
A team may be very careful in assuming technical debt. But
say due to product acquisition or bug in library used, team gets technical debt.
Minimum sprint
payment
Team may decide to pay back technical debt in regular sprint
cycle to manage total debt in reasonable limits. This is achieved by choosing
debt paying stories in each sprint.
30 days, same as cash
Sometime paying debt immediately does not result in any
interest. For example, in few initial sprints, there is no continuous integration.
Retiring Debt
Unlike financial debt, when a product is retired, all
technical debt also retires. You do not pay it J.
As product reaches end of life, cost to pay technical debt
may not be justifiable.
Parting Notes
Unlike Financial debt, you may not pay back technical debt.
In some cases paying back technical debt may not have any technical &
financial justification. For example Technical debt in case of:
·
product is reaching at end of life
·
part of code which is not evolving/changing
need not to be paid.
Therefore, In case of Technical debt probability should also be a factor
while paying it back.
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