Inmesurable PLOTS

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hdelaconcha
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Joined: Mon Jul 11, 2016 8:10 pm
Location: Mexico
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Inmesurable PLOTS

Post by hdelaconcha » Thu Dec 22, 2016 4:23 pm

In the planning process I included a 10% amount of plots just in case we could not measure some plots and stay behind the desired sample size. Now that I am about to start sending data I was wondering how does the model handle plots that we mark as 1% Measured (because it will not take a 0%). Does it include them into the calculation of the Std. error of the data. Or should I just delete them so they will not affect the statistics?? Thnaks
Horacio de la Concha
AGRINET SA de CV
Cuernavaca MEXICO
hdelaconcha@agrinet.com.mx
azelaya
i-Tree Team
Posts: 348
Joined: Fri Jun 27, 2008 10:50 am

Re: Inmesurable PLOTS

Post by azelaya » Thu Dec 29, 2016 12:29 pm

Response below was sent directly to user via email and copied here for others:

Typically if you are not able to collect data for a plot you would not enter it as complete and would not submit it from the mobile device. However if in your general workflow you like to have plots removed from the mobile device once you have visited them, then you can mark them 1% measured. However, when you bring those plots into your project, it is important that you change them so that they are not marked complete under that column. Just uncheck the box in Data>Inventory>Plots table. If a plot is not marked complete, it will not be included in the statistical calculations. It can be useful to leave those plots in the project in case there is a remauresument of the project in the future but by not marking them complete they will be ignored for all calculations.

If you mark those plots as 1% measured and include them in data submitted for processing, they will have a significant impact on the statistical calculations. The way that i-Tree Eco accounts for plots of different sizes or different percentages measured is to determine what the average plot size is and use that value for all plots. This would mean that those plots marked as 1% measured would greatly reduce that average plot size but the data they contained would be weighted the same as fully measured plots.

If you are finding that there is a pattern to plots that you are unable to access you will want to be careful that your sample is still representative of your area of interest. For example if all of your unmeasurable plots are on residential properties you would want to try to replace those plots with random residential plots as well.
A member of the i-Tree Team
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