TOPIC: Risk management

for classification of risks there are 4 types known known , unknown ,unknown ,known unknown ,unknown known , in PMOK guide 6th edition it is mentioned that unknown unknown will be managed via management reserve and known known will be managed via contingency reserve what about the other two types known known and unknown know how these types will managed if it discovered at any time through project life cycle

Known Knowns and Known Unknowns can typically be dealt with proactively either through risk response strategies, or assigning contingency reserve.

Unknown Knowns and Unknown Unknowns are dealt with reactively. Unknown Knowns are a bit more difficult to conceptualize but I take it to mean somebody has the info, but it hasn't been communicated. You would need to react accordingly to these risks - either with a workaround or management reserves.

thanks for your response but i have requested for one clarification is there any relation between classification of risks based on known -unknown and classification based on event and non event as mentioned in PMBOK6 page 398

Raed, not sure I understand your question. Those are two different ways you can classify risks.

yes there are different ways for classification of risks but my concern is there any relation between the non event risks (variability risks and ambiguity risks) and (known-unknown , unknown-known) because i did not understood well these non event risks.

I work in Construction, so variability risks for me would be performance of folks in the field, or weather conditions. These are things that we can estimate based on the past, or have a Monte Carlo done to simulate the impact.

Ambiguity risks would be things that are much more difficult to estimate or model, for instance if you're using a new technology, or even as we're seeing now during covid the volatility of market conditions. You can also simulate these, but without good assumptions the impact can vary greatly. I would typically rely on subject matter experts, and benchmarking based on what others have experienced.