SSmohnsrho and start year

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Massimiliano Cardinale, modified 4 Years ago.

SSmohnsrho and start year

Youngling Posts: 40 Join Date: 2/23/17 Recent Posts

Hej everybody and I hope all of you is having a good summer, I use often SSmohnsrho but I have a doubt about the use of the startyr in the function. I have tested SSmohnsrho changing the startyr but i always get the same results. If I run:

SSmohnsrho (retroSummary, endyrvec = endyrvec, startyr = 2013)

I get:

$AFSC_Hurtado_SSB [1] -0.0927447 $AFSC_Hurtado_Rec [1] 1.651444 $AFSC_Hurtado_F [1] 0.1117054

If I run:

SSmohnsrho (retroSummary, endyrvec = endyrvec, startyr = 2016)

I get:

$AFSC_Hurtado_SSB [1] -0.0927447 $AFSC_Hurtado_Rec [1] 1.651444 $AFSC_Hurtado_F [1] 0.1117054

So exactly the same values irrespective of the starting year.

Cheers

Max

Kathryn Doering, modified 4 Years ago.

RE: SSmohnsrho and start year

Youngling Posts: 57 Join Date: 2/19/19 Recent Posts

Hello Max,

I just took a look at the source code for the function (https://github.com/r4ss/r4ss/blob/master/R/SSmohnsrho.R) and it looks like startyr is intentionally not used for the calculation of the Alaska Fisheries Science Center and Hurtado-Ferro et al. (2015) Mohn's rho. (See this part of the code: https://github.com/r4ss/r4ss/blob/master/R/SSmohnsrho.R#L76-L99 ). startyr is a necessary input because it is used in the Wood's Hole Mohn's Rho (there is a mention of this in the documentation here: https://github.com/r4ss/r4ss/blob/master/R/SSmohnsrho.R#L14)

Hope this helps - I have never actually used this function, so if anyone has more experience with this function than I do and wants to elaborate, feel free to jump in!

Thanks,

Kathryn

Massimiliano Cardinale, modified 4 Years ago.

RE: SSmohnsrho and start year

Youngling Posts: 40 Join Date: 2/23/17 Recent Posts

Thanks for your quick reply, I did some test and you are of course correct. To change the years used to calculate the Hurtado indices, you need to change the retrosummary, so in other words the number of years used for the retrospective analysis. I though that startyear in the function would do that but it is not the case. So just change the years used by SSsummarize and it will do the trick:)

Cheers

Max