Hello,

> 

> I have count data that illustrate the presence or absence of 

> individuals in my study population. I created a grid of 563 cells
across the 

> study area and calculated a count value for each individual per season


> per year for each grid cell. The count value is the number of times an


> individual was present in each grid cell.  For illustration my data 

> columns look something like this and are repeated for each individual:

> 

> Cell_ID   Param1      Param2      Param3      Param4      COUNT Name
Year  Season      Cov

> 1         160.565994  729.08      1503        7930.3      0     AA
2010  AUT         Open

> 1         160.565994  729.08      1503        7930.3      22    AA
2011  SPR         Open

> 1         160.565994  729.08      1503        7930.3      12    AA
2009  SUM         Open

> 1         160.565994  729.08      1503        7930.3      0     AA
2010  SUM         Open

> 2         169.427001  491.87      1503.31     5101.09     0     AA
2010  AUT         oldHard

> 2         169.427001  491.87      1503.31     5101.09     16    AA
2011  SPR         oldHard

> 2         169.427001  491.87      1503.31     5101.09     0     AA
2009  SUM         oldHard

> 2         169.427001  491.87      1503.31     5101.09     0     AA
2010  SUM         oldHard

> ...                                                   

> 563       86.777099   612.69      977         4474.6      62    AA
2010  AUT         Water

> 563       86.777099   612.69      977         4474.6      12    AA
2011  SPR         Water

> 563       86.777099   612.69      977         4474.6      55    AA
2009  SUM         Water

>                                                     

>                                                     

> 1         160.565994  729.08      1503        7930.3      0     BB
2010  SUM         Open

> 2         169.427001  491.87      1503.31     5101.09     72    BB
2010  SUM         oldHard

> 5         160.75      614.95      1503.31     2878.98     16    BB
2010  SUM         medHard

> 6         170.404998  510.58      1489.44     743.14      0     BB
2010  SUM         Water

> ...                                                   

> 563       86.777099   612.69      977         4474.6      0     BB
2010  SUM         Water

>                                                     

>                                                     

> 1         160.565994  729.08      1503        7930.3      14    C
2005  AUT         Open

> 1         160.565994  729.08      1503        7930.3      0     C
2006  AUT         Open

> 1         160.565994  729.08      1503        7930.3      0     C
2006  SPR         Open

> 1         160.565994  729.08      1503        7930.3      56    C
2007  SPR         Open

> 1         160.565994  729.08      1503.       7930.3      0     C
2006  SUM         Open

> 2         169.427001  491.87      1503.31     5101.09     124   C
2005  AUT         oldHard

> 2         169.427001  491.87      1503.31     5101.09     231   C
2006  AUT         oldHard

> 2         169.427001  491.87      1503.31     5101.09     889   C
2006  SPR         oldHard

> 2         169.427001  491.87      1503.31     5101.09     0     C
2007  SPR         oldHard

> ...                                                   

> 563       86.777099   612.69      977         4474.6      0     C
2005  AUT         Water

> 563       86.777099   612.69      977         4474.6      231   C
2006  AUT         Water

> 563       86.777099   612.69      977         4474.6      185   C
2006  SPR         Water

> 563       86.777099   612.69      977         4474.6      123   C
2007  SPR         Water

> 563       86.777099   612.69      977         4474.6      52    C
2006  SUM         Water

> 

> 

> 

> I have 563 grid cells across my study area and each individual has 

> 1-563 cells associated for each year and each season the individual
was monitored.

> Therefore my grid cells are repeated and individuals may have over
2,000 records each. I end up with 71,000 records and 

> 925 records have a Count value >0; which means 70,075 records have a 

> Count value = 0.

> 

> I wanted to run a zero inflated poisson model to determine mixed 

> effects (of parameters) with individual, year, and individual nested
within year as the random effects. I have been 

> advised two things:

> 

> 1. I cannot run a zero inflated poisson model because my data are too 

> "extremely" inflated (i.e. 70,075 vs 925) and

> 

> 2. I cannot run the model with each cell repeated for each individual.


> I am told the model doesn't recognize that Cell_ID #1 for individual 

> "A" is the same Cell_ID #1 for individual "B".

> 

> Does anyone know if either or both of these points are true? I am new
to mixed modeling and programming in R, therefore I would 

> appreciate any thoughts, advice, or suggestions. I posted this
information to R-help and had two very nice replies, part of which was
suggesting I post to this site.

> 

> Thanks again for any assistance.

> 

> -Stephanie

 

 

 

-------------------------------------------------------

Stephanie L. Simek

Carnivore Ecology Lab

Forest and Wildlife Research Center

Mississippi State University

Box 9690

Mississippi State, MS 39762

Cell: (850) 591-1430

Email: ssimek@cfr.msstate.edu




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