Date created: August 5, 2017
Latest date updated: September 13, 2017

SYNOPSIS

The purpose of this report is to address AVANSE INDICATOR 1.1 EG.3-6,7,8 (FORMERLY F, FTF 4.5-16, 17, 18 FARMER’S GROSS MARGIN PER HECTARE, PER ANIMAL OR PER CAGE OBTAINED WITH USG ASSISTANCE (RAA) for the Winter campaign. The gross margin is the difference between the total value of smallholder production of an agricultural commodity (crop, fish, milk, eggs, live animals) and the cost of producing that commodity, divided by the total number of units in production (hectares of crops, pond area in hectares for pond aquaculture, cage count for open water aquaculture, number of animals in the herd for live animal sales, number of producing cows or hens for dairy or eggs). Gross margin per hectare, per animal and per cage is a measure of net income from that farm, fisheries, or livestock activity.

Gross margin is calculated automatically by FTFMS from the following data points, reported as totals across all direct beneficiaries, and disaggregated by commodity and by sex:

  1. Targeted commodity (i.e.type of crop) as per FTFMS;
  2. Sex of beneficiary farmer: Male, Female, Joint Association-applied

Gross margin per ha, per animal, per cage = [(TP x VS/QS) - IC ] / UP. It is more explicitly expressed by the formula below: \[\frac{\frac{Total~production*Total~value~of~sales}{Volume~of~sales} - {Inut~costs}}{Total~hectares~planted}\]

Unit of Measure: is dollars/hectare (Haitian gourdes will be converted to USD when reporting results). Gross margin is calculated from five(5) data points:

  1. Total Production (kg, mt, number, or other unit of measure) by all direct beneficiaries during the reporting period (TP);
  2. Total Value of Sales (U.S. dollars) by all direct beneficiaries during the reporting period (VS);
  3. Total Quantity of Sales (kg, mt, number or other unit of measure) by all direct beneficiaries during the reporting period (QS);
  4. Total Recurrent Cash Input Costs (U.S. dollars) of all direct beneficiaries during the reporting period (IC);
  5. Total Units of Production: Area planted in ha (for crops); Area in ha (for aquaculture ponds); Number of animals in herd for live animal or meat sales; Number of animal in production for dairy or eggs; Number of cages for open water aquaculture for direct beneficiaries during the production period (UP).

We have used a sample of 367 farmers dataset from the rice mobile data collection launched by the GIS Specialist. We have explored the relationship between a set of variables and Gross margin per hectare. We have choosen on the basis of specific criteria a model that gives us a better sample mean. With this model we have illustrated that Gross margin mean of female farmers is 1262 US dollars and Gross margin mean of male farmers is 1235 US dollars. A test statistic tells us there is not a difference in Gross margin mean between male and female farmers.

SAMPLE SIZE

The formula for calculating the initial sample size for the estimation of indicators of totals is given by: \[initial~sample~size~=~n_{initial}~=~\frac{N^2*z^2*s^2}{Total~hectares~planted}\] Where:

Components of the Formula

The following section provides a description of each of the components of the sample size formula given above, along with recommendations on how to estimate each of them.

Total Number of Beneficiaries (N). The first component of the formula is N, which is the total number of beneficiary farmers participating in the relevant project interventions tracked by the above indicator at the time of the design of the survey. N includes only smallholder beneficiary, producers engaged in land-based agriculture.

Critical Value from the Normal Probability Distribution (z). The next component is z, the critical value that is a fixed value from the Normal Probability Distribution, which is one of the most commonly used probability distributions in statistics and which follows the well-recognized “bell” shape. The point on the Normal Probability Distribution curve corresponding to a 95% “confidence level” 32 is typically chosen; this corresponds to a critical value of 1.96 on the Normal Probability Distribution. Therefore, Feed the Future IPs should use a fixed value of z = 1.96 for the purposes of calculating sample sizes in the current context.

Standard deviation (s) of the distribution of beneficiary data. The third component of the sample size formula is s, the standard deviation of the distribution of beneficiary data. This standard deviation is a measure of dispersion in the beneficiary-level data around the central value in the sample distribution and provides an indication of how much variation there is in the individual data points. The standard deviation is expressed in the same units as the indicator itself, and can be calculated directly from survey data.

Margin of error (MOE). The final component of the sample size formula is MOE, the margin of error, which is the half-width of a confidence interval around the estimate of the indicator representing a total, and is expressed in the same units as the indicator used as a basis for the sample size calculation. A smaller MOE results in a larger sample size, whereas a larger MOE results in a smaller sample size.
There is no generalized rule of thumb for specifying the value of the MOE to use in the sample size calculation relating to indicators of totals. However, an estimate can be obtained for the MOE using the following formula: \[MOE = p*target~value~of~indicator\] This formula has two terms. The first term, p, denotes an acceptable percentage error, and is typically subjectively specified to range between 5% and 10% (expressed as p = 0.05 and p = 0.10, respectively). Specifying p = 0.05 will result in a sample size that is greater (and often much greater) than specifying p = 0.10. For purposes of Feed the Future annual performance monitoring for both FFP and non-FFP projects, p = 0.10 should be used, unless this results in an overall survey sample size of less than 525 beneficiaries, in which case a sample size of 525 should be adopted. More detail on this guidance is provided in Section 9.2.5. The second term, target value of indicator, is set by the IPs in their indicator performance tracking tables (IPTTs) as the target value for the indicator to be achieved in the year in which the survey is being conducted.

More on normal distribution


INPUT DATA

The structure of the AVANSE beneficiary database launched by our STTA John Deriggi is mainly composed of beneficiary, distribution, training and new technology dataset. In addition, local spatial database contains parcel data which are related to beneficiary data. Based on beneficiary and parcel data, AVANSE database has been extented through mobile data collection, to address rice Gross margin, indicator.

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Mobile data collection use googlesheets as database. Though it is a semi-structured dataset, it allows to orgnaize data by type of agriculture operation as per Excel spreadsheet. Data are downloaded and read in an Integrated Development Environment(RStudio) via the googlesheets library.

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DATA PROCESSING

At this step, we summarize total production, input costs, volume of sales, values of sales by farmer. We manage inconsistent, missing and outlier values through an extensive data cleaning process. We find pattern and do replacements. For examples, 999 and missing values is replaced by zero; bidon, a local unit of total production, is converted in kg. We read landscape spatial data like river and road as they will be used in spatial ovelay analysis and thematic maps. Show more



EXPLOROTARY ANALYSIS


Here we plot the mean value of Total production in gourdes and we are trying to understand how it is different from sales, seeds and other types of use. We can see that sales value is higher over cadeau, consommation, paiement metayage, semences value. Nontheless, male producers tend to sale more rice than female farmers.

We group Total production value (expressed in gourdes) by type of use disaggregated by sex or commune. We are exploring how it is different between sales, feeding, gift, seeds and land billing use.

Rice Encadreurs entered volume of production twice. Rather than measuring directly at parcels level average volume of production by square method, after collecting volume of production through multi-use responses, they converted previous data into kg. It turned out an important inconsistency in calculation and oulier results. Encadreurs explained that This option was driven due to yield activities conducted by farmers prior to data collection.
We are exploring how correlated are those sources of data. The correlation is equal to 0.89. They are strongly correlated. Nonetheless, data from direct questions to farmers are more reliable, They will be considered in Gross margin calculation.

Here we plot the frequency of Gross Margin. We can see that the distribution is skewed at high gross margin values and the highest frequency is 189. Nonetheless, frequency is very low at High Gross margin value. It is clearly illustrated in the table below. Note that we have eleven(7) farmers with negative Gross margin value in the range of 0 to -13370 HTG. We will be examining how those value are distributed between male and female farmers
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Table 1. Gross margins frequency obtained by rice farmers in Northern Corridor

x Freq relFreq Cumul relcumul
(-1.34e+04,8.66e+04] 237 0.6528926 237 0.6528926
(8.66e+04,1.87e+05] 113 0.3112948 350 0.9641873
(1.87e+05,2.87e+05] 4 0.0110193 354 0.9752066
(2.87e+05,3.87e+05] 8 0.0220386 362 0.9972452
(3.87e+05,4.87e+05] 0 0.0000000 362 0.9972452
(4.87e+05,5.87e+05] 1 0.0027548 363 1.0000000

Here we smooth the relationship between Gross margin per hectare (GM/ha) and Input Costs. We are looking how this relationship is different between male and female farmers. We remove rows containing non-finites and missing values. There’s a positive relationship and it seems to be stronger for male farmers. Notice that we have nine(5) male farmers and only two(2) female farmers with negative Gross margin per hectare.

We explore Gross margin, expenses, area data. The red line is the linear regression, blue and green dots is respectively male and female farmers. The graph above shows that expenses and area_ha are poorly correlated with Gross margin. Nonetheless, they seems to have a good correlation between them. In addtion, these variables might have no variability in them and would no be useful covariates. We will identify if they have a very little variability.

##              freqRatio percentUnique zeroVar   nzv
## superficie        1.25      82.56131   FALSE FALSE
## cost_plowing      1.20      35.42234   FALSE FALSE

Input cost and area_ha have good variability and should be used in the model selection algorithm. We will be focusing on Gross margin as outcome and the set of variables: expenses, area_ha, and sex in our model selection process.

REGRESSION MODEL

Is there a difference in average Gross Margin per hectare between male and female farmers?

In this exercice, we are going to build a model. We include as per our exploratory analysis expenses and sex as explanatory variables and Gross Margin per hectare as outcome. The basic objective is to determine Gross margin mean from a 367 sample of farmers

Model1

##                  Estimate   Std. Error    t value     Pr(>|t|)
## (Intercept)  8.192205e+04 6141.6390765 13.3387927 2.924888e-33
## Input_costs -6.627864e-02    0.1841203 -0.3599746 7.190772e-01
## sex         -1.270776e+03 6429.0766937 -0.1976608 8.434220e-01

We grap only Cost coefficients. Its Estimated value is -0.06. So we estimate an expected 0.06 HTG decrease in Gross margin per hecatare for every 1% increase in value of Input Cost in holding the sex variable constant.
Notice that The t-test for \(H_0: \beta_{Input_costs} = 0\) versus \(H_a: \beta_{Input_costs} \neq 0\) has a P-value equal to 0.71 greater than 0.05. it is not significant.

Model2

##               Estimate Std. Error    t value     Pr(>|t|)
## (Intercept)  80765.704   5228.268 15.4478887 1.102362e-41
## factor(sex)1 -1694.753   6312.647 -0.2684695 7.884913e-01

If we include only sex, the estimate is now -1694.753, but the P-value is 0.788 greater than 0.05. The test statistic is not significative. Notice that we have only sex1, male farmer in the table. It is because R has elected to choose sex0: female farmer as the reference category. The number -1694.753 HTG is the estimated decrease in Gross margin per hectare comparing male to female farmers.

Confidence interval

## 
##  Welch Two Sample t-test
## 
## data:  Gross_margin by factor(sex)
## t = 0.31734, df = 329.46, p-value = 0.7512
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -8810.92 12200.43
## sample estimates:
## mean in group 0 mean in group 1 
##        80765.70        79070.95

If we were willing to choose the model 2 as our best model, then the confidence interval for the -1694.753 HTG Gross margin difference between male and female farmers would be -8810.92 and 12200.43.

Residuals and Diagnostic


The first graph is the unajusted one. It shows a poor relationship. You have also seen in the exploratory analysis the confounder Cost is poorly correlated with sex. We can remove the effect of Cost by taking it out of sex. You can see that once we factor out Cost, we have a relationship slightly modified, and it’s basically saying if we were to fix the unajusted model2, what you would see is a slighty modified slope.

Model3

##              Estimate Std. Error  t value     Pr(>|t|)
## factor(sex)0 80765.70   5228.268 15.44789 1.102362e-41
## factor(sex)1 79070.95   3537.615 22.35148 4.360560e-70

If we omit the intercept, then the model includes both male and female farmers. Now male is not a linear combination of female, there’s two(2) means in the dataset. The expected value of the outcome should be the mean for male or female farmers. As we can see in the table Gross margin per hectare is respectively 79070.95 and 80765.70 for male and female farmer and it is clearly illustrated in the boxplot and the pie chart below.


If I were to substract 79070.95 to 80765.70, I would get exactly -1694.75. In other words, model2 and model3 are perfectly consistent. If you are going to fix the mean of male and female farmers, any way you do this, the models will always be consistent.

CONCLUSION 1

In the second and third model, we have illustrated average Gross margin per herctare between male and female farmers and a Gross margin difference of -1694.753 HTG. However the P-value is 0.788, greater than 0.05. We fail to reject the null hypothesis and claim that there is not a difference in Gross margin mean between male and female farmers.

RICE VALUE CHAIN ANALYSIS

Rice is beconming an important cash and food crop in Northern corridor since the intervention of AVANSE project. Between Base Year 2014 and Year 2016, rice gross margin grew by 78% (from $217.96 to 1,020/ha), mainly due to favourable techniques(SRI), the development of improved seeds and the high level of prices in the domestic market which constitute a strong incentive for farmers.

Rice Value Chain Actors

  1. Producers

The most common variety grown by farmers is “Jaragwa”. They grow this variety because of its precocity(cultural cycle does not exceed three(3) months), its transformation rate(roughly 70%) and its delicious flavor. Once rice is harvested, it is threshed and winnowed at farm level. Then the unshelled rice is transported to rice mill sites or are sold to “madan sara” at farms. In theory, farmers tend to favour milling before selling as it adds substantial value to the commodity. However, it is not pratically possible, because they do not have milling machine that can process large quantities. They are forced to send paddy rice to millers. In most cases, individual farmers do not have liquidity to pay transportation from farm to miller. Also the need for immediate cash to pay household daily expenses forces farmers to sell their rice as paddy at farm level directy to “madan sara”.

  1. Madan sara

They go around harvested farms and collect directly rice based on transportation constraint of farmers. The paddy rice which is collected is then hot and/or dried, milled via (individual miller), cleaned and sold to wholesalers. They might store it to sell it to conumers as well. Rice hot which is a type of process to have shelled rice is a very popular marketing rate at consumers level. Farmers tend to sell rice to Madan sara for this specific treatment.

  1. Millers

They buy on site paddy rice from farmers. The unshelled rice is then dried, milled, cleaned, packaged, stored and sold to wholesalers or directly to consumers.

  1. Wholesalers

They buy Milled rice from Millers and sell it to rural retailers.

  1. Rural retailers

They use either “madan sara” or millers sold rice and they sell it to consumers.

Rice Value Chain Mapping



Gross Margin Analysis

Generally, the average cost of producing rice was greater in Ouanaminthe, Fort-Liberte, Acul-du-Nord, Perches and Ferrier. Harvesting is a costly operation in Ouanaminthe, Fort-Liberte, and Ferrrier since moisonneuse batteuse is increasingly used in these communes. However average gross margin per hecare value in Ouanaminthe is:44303 HTG/ha, the lowest value among farmers zones as highlighted in the cloud representation below.
We can see that Acul-du-Nord and Milot have big sizes. It is simply says that Gross margin mean is more important at Acul-du-Nord and Milot.

Though Ploughing and harvesting were the most costly operation to rice farmers in that area, they cannot explain this low value of gross margin in Ouanaminthe because other communes like Ferrier have cosly Ploughing and harvesting expenses but gross margin values are highly greater than Ouanaminthe. Thematic maps below illustrate the spatial variation of harvesting and plowing input cost in Perches and Acul-du-Nord

The map above illustrates harvest expenses per hectare in Ferrier using Kernel density. It calculates the density of parcels in a neighborhood around those parcels. In non-technical terms, this means that the value of each parcel harvest expenses is spread around its vicinity. Rather than a literal interpretation, the interpretation here is qualitative or relative. It is simply says that purple darker colored area have more parcels around them but their harvest expenses is lower comparing lighter colored area.

Table 2. Gross margins and expenses mean per hectare obtained by rice farmers in Northern Corridor

Cost_and_Gross_margin ACUL_DU_NORD FERRIER FORT_LIBERTE MILOT OUANAMINTHE PERCHES PLAINE_DU_NORD
Gross_margin 106774 88039 75987 59916 94552 44303 126533
Input_costs 37858 41442 38916 41786 18432 35714 48508
cost_plowing 10247 11792 7294 8844 10861 8787 9321
cost_seeds 0 8 516 0 0 109 306
cost_nursery 259 700 1350 1990 373 316 668
cost_transplanting 4244 4226 5692 7075 2743 5112 13808
workforce_pesticides 0 338 388 774 0 304 233
cost_pesticides 0 2339 537 0 0 1288 361
cost_herbicides 1029 1135 1904 774 154 168 1899
cost_weeding 1767 1158 3501 884 1744 5776 5323
cost_application 0 574 285 221 0 280 276
cost_fertilizer 10823 7460 5269 3316 329 5171 8395
irrigation_cost 0 195 1366 3980 13 247 0
fees_cost 0 128 45 0 205 365 0
other_cost 2280 36 0 0 0 36 0
post_harvest_cost 93 48 70 0 0 85 0
harvest_cost 3792 9655 8218 10612 1072 6606 6926
cost_channel 3325 1648 2482 3316 936 1064 993


Graph 2. Gross margins and expenses mean per hectare obtained by rice farmers in Northern Corridor

## geom_path: Each group consists of only one observation. Do you need to
## adjust the group aesthetic?

Here we are trying to illustrate the frequency of harvesting methods among communes. We can see that Ouanaminthe, Ferrier et Fort-Liberte tends to use moisonneuse batteuse equipment more than other communes.

Table 3. Harvesting method versus rice farmers sites

Main d’oeuvre Moisonneuse batteuse
ACUL DU NORD 50 0
FERRIER 9 67
FORT LIBERTE 112 19
LIMONADE 1 0
MILOT 35 1
OUANAMINTHE 54 7
PERCHES 12 0
PLAINE DU NORD 10 0

Purple darker colored area have more parcels around them but their harvest expenses is lower comparing lighter colored area.

## Warning: Removed 4 rows containing missing values (geom_point).

## Warning: Removed 4 rows containing missing values (geom_point).

CONCLUSION 2

We have illustrated mean of Gross margin per hectare difference among communes. We have attempted to explain the low gross margin value in Ouanaminthe. Further analysis in other area of activities is required to help us determine this gross margin average difference.