This page contains the list of check-boxes included in the Statistics step of the assessment wizard; these check-boxes give you the capability to customize the output of the dietary and residential assessments. The list changes according to the options selected in the previous steps of the wizard. In particular, it depends on the type of assessment and the time frame chosen in the first step of the wizard. This tutorial presents a summary of all the options that can be available.
List of the options
# Of Iterations
This option is available in the Acute, Multi-day and Within-day dietary assessments. In these assessments it is possible to increase the number of simulated subjects, if wanted, by replicating each of them a number of times. This number corresponds to the number of iterations. It can be provided as input by selecting this option and then typing the number of iterations in the input field which opens below.
This option is available in the Acute, Multi-day and Within-day dietary assessments. These are probabilistic assessments because they use distributions of residue values which are randomly sampled at each run of the assessment. This option allows you to run assessments with an exact replica of the probabilistic component. It is useful for example when comparing results of two assessments to eliminate the differences that originate purely from the execution of random processes. This option gives you the capability to re-run the assessment by performing the exact replica of the previous run. In order to do this, you have to select this option and type the same seed number in the input field in both runs of the assessment.
Include absolute exposure
By default, the dietary assessment calculates the exposure levels to the analysed chemical(s) per unit body-weight. This means that each exposure level is divided by the body-weight of the exposed subject. If you select this option, the dietary assessment also calculates the absolute exposure, namely the exposure levels will not be divided by the body-weight of the exposed subjects, together with the exposure per body-weight. This option is available for the dietary assessments only.
Margin of Exposure (MOE)
This option is available in the Aggregate and Cumulative assessments of both the dietary and the residential model. The MOE is the ratio between the toxicological Point of Departure (POD) and the exposure levels of the chemical(s) under analysis.
Hazard Index (HI)
This option is available in the Aggregate and Cumulative assessments of both the dietary and the residential model. The HI is the ratio between the exposure levels and the Population Adjusted Doses (PADs) of the chemical(s) under analysis. The PADs are equal to the PODs divided by the Uncertainty Factors (UFs) provided in the chemical table.
Aggregate Population Adjusted Dose (aPAD)
This option is available in the Aggregate assessments of both the dietary and the residential model. The aPAD is equal to the HI multiplied by 100 and shown as a percentage.
Cumulative Risk Index (CRI)
This option is available in the Cumulative assessments of the dietary model. The CRI is the ratio between the Population Adjusted Doses (PADs) of the index chemical and the cumulative exposure dose. The PADs are equal to the PODs divided by the Uncertainty Factors (UFs) provided in the chemical table. Please refer to the page Cumulative risk characterization for more information.
Residue/Food Match Level
This option is available in the Acute, Multi-day and Within-day assessments and it gives you the capability to decide if you prefer to match the residue data with the food consumption data at eating event or day level. In case you select the ”Eating Event” option, the assessment will randomly select a new residue value for each eating event (breakfast, lunch, dinner, etc.) when the food(s) are consumed. Otherwise, the assessment will assign a unique residue value for each food to all the eating event occurring in the same day.
This option is available in the Multi-day and Within-day dietary assessments only. These assessments create a 365-day food consumption diary for each subject under analysis. The diary is the outcome of these two statistical methods:
- Temporal repeating diet: the same 2-day data, recorded in the NHANES survey, for the same person will be randomly selected as many times as it is necessary to cover the exposure period of 365 days. Only diaries with two survey days will be used.
- Temporal match diet: the diary of each subject contains his/her 2-day food consumption data recorded in the NHANES surveys and the 2-day data of other NHANES neighbours. Each food consumption day, coming from both the subject him/herself and one of his/her neighbours, can be used more than once in order to fill the whole 365-day diary. The number of times each day must be used is fixed but the order changes at each run of the model.
The Chronic (dietary and residential) and Cancer are deterministic assessment; hence no statistics are calculated for these assessments. In the Acute, Multi-day and Within-day assessments you are presented with the following options:
- Per capita: by default, the assessments calculate the statistics over the exposure levels of the user-only subject, namely those subjects who consumed the foods under analysis. If you select this option, the assessments calculate the statistics over the whole population, taking into account both users and non-users.
- Specific percentiles: you can input a list of percentiles that you want the assessment to calculate
More output options
This option contains a unique check-box: Include Intermediate Calculations. If you select it, the assessment produces the tables created in the intermediate steps of the dietary assessments together with the default output which contains the summary statistics of the exposure level distributions calculated in the intermediate steps. In the Within-day assessment, this check-box is called Include Intermediate Calculations (PBPK output).